diff --git a/README.md b/README.md
index b84aace..ea390aa 100644
--- a/README.md
+++ b/README.md
@@ -5,7 +5,7 @@
 ## Features:
 * Built in support for +, -, *, /, % and power (^) operators
 * Paratheses () and arrays [] are fully supported
-* Logical operators (==, !=, <, <, >=, <=, &&, ||)
+* Logical operators (==, !=, <, <, >=, <=, &&, ||, !)
 * Built in support for most PHP math functions
 * Support for BCMath Arbitrary Precision Math
 * Support for variable number of function parameters and optional function parameters
@@ -71,6 +71,7 @@ Default functions:
 * log10 (lg)
 * log1p
 * max
+* median
 * min
 * octdec
 * pi
@@ -125,7 +126,7 @@ $executor->addOperator(new Operator(
 ```
 
 ## Logical operators:
-Logical operators (==, !=, <, <, >=, <=, &&, ||) are supported, but logically they can only return true (1) or false (0).  In order to leverage them, use the built in **if** function:
+Logical operators (==, !=, <, <, >=, <=, &&, ||, !) are supported, but logically they can only return true (1) or false (0).  In order to leverage them, use the built in **if** function:
 
 ```
 if($a > $b, $a - $b, $b - $a)
diff --git a/src/NXP/MathExecutor.php b/src/NXP/MathExecutor.php
index c857e99..84dd3d9 100644
--- a/src/NXP/MathExecutor.php
+++ b/src/NXP/MathExecutor.php
@@ -85,10 +85,10 @@ public function addOperator(Operator $operator) : self
     /**
      * Execute expression
      *
-     * @throws Exception\IncorrectBracketsException
      * @throws Exception\IncorrectExpressionException
      * @throws Exception\UnknownOperatorException
      * @throws UnknownVariableException
+     * @throws Exception\IncorrectBracketsException
      * @return int|float|string|null
      */
     public function execute(string $expression, bool $cache = true)
@@ -113,7 +113,7 @@ public function execute(string $expression, bool $cache = true)
     /**
      * Add function to executor
      *
-     * @param string        $name     Name of function
+     * @param string $name Name of function
      * @param callable|null $function Function
      *
      * @throws ReflectionException
@@ -182,8 +182,8 @@ public function varExists(string $variable) : bool
     /**
      * Add variables to executor
      *
-     * @param  array<string, float|int|string> $variables
-     * @param  bool $clear Clear previous variables
+     * @param array<string, float|int|string> $variables
+     * @param bool $clear Clear previous variables
      * @throws \Exception
      */
     public function setVars(array $variables, bool $clear = true) : self
@@ -285,7 +285,7 @@ public function removeOperator(string $operator) : self
      */
     public function setDivisionByZeroIsZero() : self
     {
-        $this->addOperator(new Operator('/', false, 180, static fn ($a, $b) => 0 == $b ? 0 : $a / $b));
+        $this->addOperator(new Operator('/', false, 180, static fn($a, $b) => 0 == $b ? 0 : $a / $b));
 
         return $this;
     }
@@ -311,23 +311,23 @@ public function clearCache() : self
 
     public function useBCMath(int $scale = 2) : self
     {
-      \bcscale($scale);
-      $this->addOperator(new Operator('+', false, 170, static fn ($a, $b) => \bcadd("{$a}", "{$b}")));
-      $this->addOperator(new Operator('-', false, 170, static fn ($a, $b) => \bcsub("{$a}", "{$b}")));
-      $this->addOperator(new Operator('uNeg', false, 200, static fn ($a) => \bcsub('0.0', "{$a}")));
-      $this->addOperator(new Operator('*', false, 180, static fn ($a, $b) => \bcmul("{$a}", "{$b}")));
-      $this->addOperator(new Operator('/', false, 180, static function($a, $b) {
-          /** @todo PHP8: Use throw as expression -> static fn($a, $b) => 0 == $b ? throw new DivisionByZeroException() : $a / $b */
-          if (0 == $b) {
-              throw new DivisionByZeroException();
-          }
-
-          return \bcdiv("{$a}", "{$b}");
-      }));
-      $this->addOperator(new Operator('^', true, 220, static fn ($a, $b) => \bcpow("{$a}", "{$b}")));
-      $this->addOperator(new Operator('%', false, 180, static fn ($a, $b) => \bcmod("{$a}", "{$b}")));
-
-      return $this;
+        \bcscale($scale);
+        $this->addOperator(new Operator('+', false, 170, static fn($a, $b) => \bcadd("{$a}", "{$b}")));
+        $this->addOperator(new Operator('-', false, 170, static fn($a, $b) => \bcsub("{$a}", "{$b}")));
+        $this->addOperator(new Operator('uNeg', false, 200, static fn($a) => \bcsub('0.0', "{$a}")));
+        $this->addOperator(new Operator('*', false, 180, static fn($a, $b) => \bcmul("{$a}", "{$b}")));
+        $this->addOperator(new Operator('/', false, 180, static function($a, $b) {
+            /** @todo PHP8: Use throw as expression -> static fn($a, $b) => 0 == $b ? throw new DivisionByZeroException() : $a / $b */
+            if (0 == $b) {
+                throw new DivisionByZeroException();
+            }
+
+            return \bcdiv("{$a}", "{$b}");
+        }));
+        $this->addOperator(new Operator('^', true, 220, static fn($a, $b) => \bcpow("{$a}", "{$b}")));
+        $this->addOperator(new Operator('%', false, 180, static fn($a, $b) => \bcmod("{$a}", "{$b}")));
+
+        return $this;
     }
 
     /**
@@ -359,15 +359,16 @@ protected function addDefaults() : self
     protected function defaultOperators() : array
     {
         return [
-          '+' => [static fn ($a, $b) => $a + $b, 170, false],
-          '-' => [static fn ($a, $b) => $a - $b, 170, false],
+          '+' => [static fn($a, $b) => $a + $b, 170, false],
+          '-' => [static fn($a, $b) => $a - $b, 170, false],
           // unary positive token
-          'uPos' => [static fn ($a) => $a, 200, false],
+          'uPos' => [static fn($a) => $a, 200, false],
           // unary minus token
-          'uNeg' => [static fn ($a) => 0 - $a, 200, false],
-          '*' => [static fn ($a, $b) => $a * $b, 180, false],
+          'uNeg' => [static fn($a) => 0 - $a, 200, false],
+          '*' => [static fn($a, $b) => $a * $b, 180, false],
           '/' => [
-            static function($a, $b) { /** @todo PHP8: Use throw as expression -> static fn($a, $b) => 0 == $b ? throw new DivisionByZeroException() : $a / $b */
+            static function($a, $b) {
+                /** @todo PHP8: Use throw as expression -> static fn($a, $b) => 0 == $b ? throw new DivisionByZeroException() : $a / $b */
                 if (0 == $b) {
                     throw new DivisionByZeroException();
                 }
@@ -377,16 +378,17 @@ static function($a, $b) { /** @todo PHP8: Use throw as expression -> static fn($
             180,
             false
           ],
-          '^' => [static fn ($a, $b) => $a ** $b, 220, true],
-          '%' => [static fn ($a, $b) => $a % $b, 180, false],
-          '&&' => [static fn ($a, $b) => $a && $b, 100, false],
-          '||' => [static fn ($a, $b) => $a || $b, 90, false],
-          '==' => [static fn ($a, $b) => \is_string($a) || \is_string($b) ? 0 == \strcmp($a, $b) : $a == $b, 140, false],
-          '!=' => [static fn ($a, $b) => \is_string($a) || \is_string($b) ? 0 != \strcmp($a, $b) : $a != $b, 140, false],
-          '>=' => [static fn ($a, $b) => $a >= $b, 150, false],
-          '>' => [static fn ($a, $b) => $a > $b, 150, false],
-          '<=' => [static fn ($a, $b) => $a <= $b, 150, false],
-          '<' => [static fn ($a, $b) => $a < $b, 150, false],
+          '^' => [static fn($a, $b) => $a ** $b, 220, true],
+          '%' => [static fn($a, $b) => $a % $b, 180, false],
+          '&&' => [static fn($a, $b) => $a && $b, 100, false],
+          '||' => [static fn($a, $b) => $a || $b, 90, false],
+          '==' => [static fn($a, $b) => \is_string($a) || \is_string($b) ? 0 == \strcmp($a, $b) : $a == $b, 140, false],
+          '!=' => [static fn($a, $b) => \is_string($a) || \is_string($b) ? 0 != \strcmp($a, $b) : $a != $b, 140, false],
+          '>=' => [static fn($a, $b) => $a >= $b, 150, false],
+          '>' => [static fn($a, $b) => $a > $b, 150, false],
+          '<=' => [static fn($a, $b) => $a <= $b, 150, false],
+          '<' => [static fn($a, $b) => $a < $b, 150, false],
+          '!' => [static fn($a) => ! $a, 190, false],
         ];
     }
 
@@ -399,28 +401,28 @@ static function($a, $b) { /** @todo PHP8: Use throw as expression -> static fn($
     protected function defaultFunctions() : array
     {
         return [
-          'abs' => static fn ($arg) => \abs($arg),
-          'acos' => static fn ($arg) => \acos($arg),
-          'acosh' => static fn ($arg) => \acosh($arg),
-          'arcsin' => static fn ($arg) => \asin($arg),
-          'arcctg' => static fn ($arg) => M_PI / 2 - \atan($arg),
-          'arccot' => static fn ($arg) => M_PI / 2 - \atan($arg),
-          'arccotan' => static fn ($arg) => M_PI / 2 - \atan($arg),
-          'arcsec' => static fn ($arg) => \acos(1 / $arg),
-          'arccosec' => static fn ($arg) => \asin(1 / $arg),
-          'arccsc' => static fn ($arg) => \asin(1 / $arg),
-          'arccos' => static fn ($arg) => \acos($arg),
-          'arctan' => static fn ($arg) => \atan($arg),
-          'arctg' => static fn ($arg) => \atan($arg),
-          'array' => static fn (...$args) => $args,
-          'asin' => static fn ($arg) => \asin($arg),
-          'atan' => static fn ($arg) => \atan($arg),
-          'atan2' => static fn ($arg1, $arg2) => \atan2($arg1, $arg2),
-          'atanh' => static fn ($arg) => \atanh($arg),
-          'atn' => static fn ($arg) => \atan($arg),
+          'abs' => static fn($arg) => \abs($arg),
+          'acos' => static fn($arg) => \acos($arg),
+          'acosh' => static fn($arg) => \acosh($arg),
+          'arcsin' => static fn($arg) => \asin($arg),
+          'arcctg' => static fn($arg) => M_PI / 2 - \atan($arg),
+          'arccot' => static fn($arg) => M_PI / 2 - \atan($arg),
+          'arccotan' => static fn($arg) => M_PI / 2 - \atan($arg),
+          'arcsec' => static fn($arg) => \acos(1 / $arg),
+          'arccosec' => static fn($arg) => \asin(1 / $arg),
+          'arccsc' => static fn($arg) => \asin(1 / $arg),
+          'arccos' => static fn($arg) => \acos($arg),
+          'arctan' => static fn($arg) => \atan($arg),
+          'arctg' => static fn($arg) => \atan($arg),
+          'array' => static fn(...$args) => $args,
+          'asin' => static fn($arg) => \asin($arg),
+          'atan' => static fn($arg) => \atan($arg),
+          'atan2' => static fn($arg1, $arg2) => \atan2($arg1, $arg2),
+          'atanh' => static fn($arg) => \atanh($arg),
+          'atn' => static fn($arg) => \atan($arg),
           'avg' => static function($arg1, ...$args) {
-              if (\is_array($arg1)){
-                  if (0 === \count($arg1)){
+              if (\is_array($arg1)) {
+                  if (0 === \count($arg1)) {
                       throw new \InvalidArgumentException('avg() must have at least one argument!');
                   }
 
@@ -431,27 +433,27 @@ protected function defaultFunctions() : array
 
               return \array_sum($args) / \count($args);
           },
-          'bindec' => static fn ($arg) => \bindec($arg),
-          'ceil' => static fn ($arg) => \ceil($arg),
-          'cos' => static fn ($arg) => \cos($arg),
-          'cosec' => static fn ($arg) => 1 / \sin($arg),
-          'csc' => static fn ($arg) => 1 / \sin($arg),
-          'cosh' => static fn ($arg) => \cosh($arg),
-          'ctg' => static fn ($arg) => \cos($arg) / \sin($arg),
-          'cot' => static fn ($arg) => \cos($arg) / \sin($arg),
-          'cotan' => static fn ($arg) => \cos($arg) / \sin($arg),
-          'cotg' => static fn ($arg) => \cos($arg) / \sin($arg),
-          'ctn' => static fn ($arg) => \cos($arg) / \sin($arg),
-          'decbin' => static fn ($arg) => \decbin($arg),
-          'dechex' => static fn ($arg) => \dechex($arg),
-          'decoct' => static fn ($arg) => \decoct($arg),
-          'deg2rad' => static fn ($arg) => \deg2rad($arg),
-          'exp' => static fn ($arg) => \exp($arg),
-          'expm1' => static fn ($arg) => \expm1($arg),
-          'floor' => static fn ($arg) => \floor($arg),
-          'fmod' => static fn ($arg1, $arg2) => \fmod($arg1, $arg2),
-          'hexdec' => static fn ($arg) => \hexdec($arg),
-          'hypot' => static fn ($arg1, $arg2) => \hypot($arg1, $arg2),
+          'bindec' => static fn($arg) => \bindec($arg),
+          'ceil' => static fn($arg) => \ceil($arg),
+          'cos' => static fn($arg) => \cos($arg),
+          'cosec' => static fn($arg) => 1 / \sin($arg),
+          'csc' => static fn($arg) => 1 / \sin($arg),
+          'cosh' => static fn($arg) => \cosh($arg),
+          'ctg' => static fn($arg) => \cos($arg) / \sin($arg),
+          'cot' => static fn($arg) => \cos($arg) / \sin($arg),
+          'cotan' => static fn($arg) => \cos($arg) / \sin($arg),
+          'cotg' => static fn($arg) => \cos($arg) / \sin($arg),
+          'ctn' => static fn($arg) => \cos($arg) / \sin($arg),
+          'decbin' => static fn($arg) => \decbin($arg),
+          'dechex' => static fn($arg) => \dechex($arg),
+          'decoct' => static fn($arg) => \decoct($arg),
+          'deg2rad' => static fn($arg) => \deg2rad($arg),
+          'exp' => static fn($arg) => \exp($arg),
+          'expm1' => static fn($arg) => \expm1($arg),
+          'floor' => static fn($arg) => \floor($arg),
+          'fmod' => static fn($arg1, $arg2) => \fmod($arg1, $arg2),
+          'hexdec' => static fn($arg) => \hexdec($arg),
+          'hypot' => static fn($arg1, $arg2) => \hypot($arg1, $arg2),
           'if' => function($expr, $trueval, $falseval) {
               if (true === $expr || false === $expr) {
                   $exres = $expr;
@@ -465,39 +467,56 @@ protected function defaultFunctions() : array
 
               return $this->execute($falseval);
           },
-          'intdiv' => static fn ($arg1, $arg2) => \intdiv($arg1, $arg2),
-          'ln' => static fn ($arg) => \log($arg),
-          'lg' => static fn ($arg) => \log10($arg),
-          'log' => static fn ($arg) => \log($arg),
-          'log10' => static fn ($arg) => \log10($arg),
-          'log1p' => static fn ($arg) => \log1p($arg),
+          'intdiv' => static fn($arg1, $arg2) => \intdiv($arg1, $arg2),
+          'ln' => static fn($arg) => \log($arg),
+          'lg' => static fn($arg) => \log10($arg),
+          'log' => static fn($arg) => \log($arg),
+          'log10' => static fn($arg) => \log10($arg),
+          'log1p' => static fn($arg) => \log1p($arg),
           'max' => static function($arg1, ...$args) {
-              if (\is_array($arg1) && 0 === \count($arg1)){
+              if (\is_array($arg1) && 0 === \count($arg1)) {
                   throw new \InvalidArgumentException('max() must have at least one argument!');
               }
 
               return \max(\is_array($arg1) ? $arg1 : [$arg1, ...$args]);
           },
+          'median' => static function($arg1, ...$args) {
+              if (\is_array($arg1)) {
+                  if (0 === \count($arg1)) {
+                      throw new \InvalidArgumentException('Array must contain at least one element!');
+                  }
+
+                  $finalArgs = $arg1;
+              } else {
+                  $finalArgs = [$arg1, ...$args];
+              }
+
+              $count = \count($finalArgs);
+              \sort($finalArgs);
+              $index = \floor($count / 2);
+
+              return ($count & 1) ? $finalArgs[$index] : ($finalArgs[$index - 1] + $finalArgs[$index]) / 2;
+          },
           'min' => static function($arg1, ...$args) {
-              if (\is_array($arg1) && 0 === \count($arg1)){
+              if (\is_array($arg1) && 0 === \count($arg1)) {
                   throw new \InvalidArgumentException('min() must have at least one argument!');
               }
 
               return \min(\is_array($arg1) ? $arg1 : [$arg1, ...$args]);
           },
-          'octdec' => static fn ($arg) => \octdec($arg),
-          'pi' => static fn () => M_PI,
-          'pow' => static fn ($arg1, $arg2) => $arg1 ** $arg2,
-          'rad2deg' => static fn ($arg) => \rad2deg($arg),
-          'round' => static fn ($num, int $precision = 0) => \round($num, $precision),
-          'sin' => static fn ($arg) => \sin($arg),
-          'sinh' => static fn ($arg) => \sinh($arg),
-          'sec' => static fn ($arg) => 1 / \cos($arg),
-          'sqrt' => static fn ($arg) => \sqrt($arg),
-          'tan' => static fn ($arg) => \tan($arg),
-          'tanh' => static fn ($arg) => \tanh($arg),
-          'tn' => static fn ($arg) => \tan($arg),
-          'tg' => static fn ($arg) => \tan($arg)
+          'octdec' => static fn($arg) => \octdec($arg),
+          'pi' => static fn() => M_PI,
+          'pow' => static fn($arg1, $arg2) => $arg1 ** $arg2,
+          'rad2deg' => static fn($arg) => \rad2deg($arg),
+          'round' => static fn($num, int $precision = 0) => \round($num, $precision),
+          'sin' => static fn($arg) => \sin($arg),
+          'sinh' => static fn($arg) => \sinh($arg),
+          'sec' => static fn($arg) => 1 / \cos($arg),
+          'sqrt' => static fn($arg) => \sqrt($arg),
+          'tan' => static fn($arg) => \tan($arg),
+          'tanh' => static fn($arg) => \tanh($arg),
+          'tn' => static fn($arg) => \tan($arg),
+          'tg' => static fn($arg) => \tan($arg)
         ];
     }
 
diff --git a/tests/MathTest.php b/tests/MathTest.php
index 2c9197f..f8573d3 100644
--- a/tests/MathTest.php
+++ b/tests/MathTest.php
@@ -256,6 +256,8 @@ public function providerExpressions()
           ['7 % 4'],
           ['99 % 4'],
           ['123 % 7'],
+          ['!(1||0)'],
+          ['!(1&&0)'],
         ];
     }
 
@@ -493,6 +495,8 @@ public function bcMathExpressions()
           ['7 % 4'],
           ['99 % 4'],
           ['123 % 7'],
+          ['!(1||0)'],
+          ['!(1&&0)'],
         ];
     }
 
@@ -600,7 +604,7 @@ public function testStringEscape() : void
         $this->assertEquals("'teststring", $calculator->execute("'\'teststring'"));
         $this->assertEquals("teststring'", $calculator->execute("'teststring\''"));
 
-        $calculator->addFunction('concat', static fn ($arg1, $arg2) => $arg1 . $arg2);
+        $calculator->addFunction('concat', static fn($arg1, $arg2) => $arg1 . $arg2);
         $this->assertEquals('test"ing', $calculator->execute('concat("test\"","ing")'));
         $this->assertEquals("test'ing", $calculator->execute("concat('test\'','ing')"));
     }
@@ -614,7 +618,7 @@ public function testArrays() : void
         $this->assertEquals(\max([1, 5, 2]), $calculator->execute('max(array(1, 5, 2))'));
         $calculator->addFunction('arr_with_max_elements', static function($arg1, ...$args) {
             $args = \is_array($arg1) ? $arg1 : [$arg1, ...$args];
-            \usort($args, static fn ($arr1, $arr2) => (\is_countable($arr2) ? \count($arr2) : 0) <=> \count($arr1));
+            \usort($args, static fn($arr1, $arr2) => (\is_countable($arr2) ? \count($arr2) : 0) <=> \count($arr1));
 
             return $args[0];
         });
@@ -625,7 +629,7 @@ public function testFunctionParameterOrder() : void
     {
         $calculator = new MathExecutor();
 
-        $calculator->addFunction('concat', static fn ($arg1, $arg2) => $arg1 . $arg2);
+        $calculator->addFunction('concat', static fn($arg1, $arg2) => $arg1 . $arg2);
         $this->assertEquals('testing', $calculator->execute('concat("test","ing")'));
         $this->assertEquals('testing', $calculator->execute("concat('test','ing')"));
     }
@@ -633,31 +637,34 @@ public function testFunctionParameterOrder() : void
     public function testFunction() : void
     {
         $calculator = new MathExecutor();
-        $calculator->addFunction('round', static fn ($arg) => \round($arg));
+        $calculator->addFunction('round', static fn($arg) => \round($arg));
         $this->assertEquals(\round(100 / 30), $calculator->execute('round(100/30)'));
     }
 
     public function testFunctionUnlimitedParameters() : void
     {
         $calculator = new MathExecutor();
-        $calculator->addFunction('give_me_an_array', static fn () => [5, 3, 7, 9, 8]);
+        $calculator->addFunction('give_me_an_array', static fn() => [5, 3, 7, 9, 8]);
         $this->assertEquals(6.4, $calculator->execute('avg(give_me_an_array())'));
         $this->assertEquals(10, $calculator->execute('avg(12,8,15,5)'));
         $this->assertEquals(3, $calculator->execute('min(give_me_an_array())'));
         $this->assertEquals(1, $calculator->execute('min(1,2,3)'));
         $this->assertEquals(9, $calculator->execute('max(give_me_an_array())'));
         $this->assertEquals(3, $calculator->execute('max(1,2,3)'));
+        $this->assertEquals(7, $calculator->execute('median(give_me_an_array())'));
+        $this->assertEquals(4, $calculator->execute('median(1,3,5,7)'));
         $calculator->setVar('monthly_salaries', [100, 200, 300]);
         $this->assertEquals([100, 200, 300], $calculator->execute('$monthly_salaries'));
         $this->assertEquals(200, $calculator->execute('avg($monthly_salaries)'));
         $this->assertEquals(\min([100, 200, 300]), $calculator->execute('min($monthly_salaries)'));
         $this->assertEquals(\max([100, 200, 300]), $calculator->execute('max($monthly_salaries)'));
+        $this->assertEquals(200, $calculator->execute('median($monthly_salaries)'));
     }
 
     public function testFunctionOptionalParameters() : void
     {
         $calculator = new MathExecutor();
-        $calculator->addFunction('round', static fn ($num, $precision = 0) => \round($num, $precision));
+        $calculator->addFunction('round', static fn($num, $precision = 0) => \round($num, $precision));
         $this->assertEquals(\round(11.176), $calculator->execute('round(11.176)'));
         $this->assertEquals(\round(11.176, 2), $calculator->execute('round(11.176,2)'));
     }
@@ -666,7 +673,7 @@ public function testFunctionIncorrectNumberOfParameters() : void
     {
         $calculator = new MathExecutor();
         $this->expectException(IncorrectNumberOfFunctionParametersException::class);
-        $calculator->addFunction('myfunc', static fn ($arg1, $arg2) => $arg1 + $arg2);
+        $calculator->addFunction('myfunc', static fn($arg1, $arg2) => $arg1 + $arg2);
         $calculator->execute('myfunc(1)');
     }
 
@@ -674,7 +681,7 @@ public function testFunctionIncorrectNumberOfParametersTooMany() : void
     {
         $calculator = new MathExecutor();
         $this->expectException(IncorrectNumberOfFunctionParametersException::class);
-        $calculator->addFunction('myfunc', static fn ($arg1, $arg2) => $arg1 + $arg2);
+        $calculator->addFunction('myfunc', static fn($arg1, $arg2) => $arg1 + $arg2);
         $calculator->execute('myfunc(1,2,3)');
     }
 
@@ -826,7 +833,7 @@ public function testEvaluateFunctionParameters() : void
         $calculator = new MathExecutor();
         $calculator->addFunction(
           'round',
-          static fn ($value, $decimals) => \round($value, $decimals)
+          static fn($value, $decimals) => \round($value, $decimals)
         );
         $expression = 'round(100 * 1.111111, 2)';
         $phpResult = 0;
@@ -840,7 +847,7 @@ public function testEvaluateFunctionParameters() : void
     public function testFunctionsWithQuotes() : void
     {
         $calculator = new MathExecutor();
-        $calculator->addFunction('concat', static fn ($first, $second) => $first . $second);
+        $calculator->addFunction('concat', static fn($first, $second) => $first . $second);
         $this->assertEquals('testing', $calculator->execute('concat("test", "ing")'));
         $this->assertEquals('testing', $calculator->execute("concat('test', 'ing')"));
     }