diff --git a/requirements-core.txt b/requirements-core.txt
index 5cb8fcd..3dc3bed 100644
--- a/requirements-core.txt
+++ b/requirements-core.txt
@@ -1,2 +1,2 @@
-numpy==1.21.5
-pandas==1.3.5
+numpy==1.19.5
+pandas==1.1.5
diff --git a/requirements-test.txt b/requirements-test.txt
index 36faeda..683beb4 100644
--- a/requirements-test.txt
+++ b/requirements-test.txt
@@ -1,5 +1,5 @@
 -r requirements-core.txt
 
 # clean code
-black==23.10.1
-prospector[with_mypy,with_bandit]==1.10.3
+black==22.8.0
+prospector[with_mypy,with_bandit]==1.7.7
diff --git a/ta/trend.py b/ta/trend.py
index 553afad..161c877 100644
--- a/ta/trend.py
+++ b/ta/trend.py
@@ -728,7 +728,7 @@ def _run(self):
 
         self._trs_initial = np.zeros(self._window - 1)
         self._trs = np.zeros(len(self._close) - (self._window - 1))
-        self._trs[0] = diff_directional_movement.dropna().iloc[0 : self._window].sum()
+        self._trs[0] = diff_directional_movement.dropna().iloc[0:self._window].sum()
         diff_directional_movement = diff_directional_movement.reset_index(drop=True)
 
         for i in range(1, len(self._trs) - 1):
@@ -745,7 +745,7 @@ def _run(self):
         neg = abs(((diff_down > diff_up) & (diff_down > 0)) * diff_down)
 
         self._dip = np.zeros(len(self._close) - (self._window - 1))
-        self._dip[0] = pos.dropna().iloc[0 : self._window].sum()
+        self._dip[0] = pos.dropna().iloc[0:self._window].sum()
 
         pos = pos.reset_index(drop=True)
 
@@ -757,7 +757,7 @@ def _run(self):
             )
 
         self._din = np.zeros(len(self._close) - (self._window - 1))
-        self._din[0] = neg.dropna().iloc[0 : self._window].sum()
+        self._din[0] = neg.dropna().iloc[0:self._window].sum()
 
         neg = neg.reset_index(drop=True)
 
@@ -804,7 +804,7 @@ def adx(self) -> pd.Series:
                 directional_index[idx] = 0
 
         adx_series = np.zeros(len(self._trs))
-        adx_series[self._window] = directional_index[0 : self._window].mean()
+        adx_series[self._window] = directional_index[0:self._window].mean()
 
         for i in range(self._window + 1, len(adx_series)):
             adx_series[i] = (
@@ -1027,7 +1027,7 @@ def _run(self):  # noqa
                     high1 = self._high.iloc[i - 1]
                     high2 = self._high.iloc[i - 2]
                     if high2 > self._psar.iloc[i]:
-                        self._psar[i] = high2
+                        self._psar.iloc[i] = high2
                     elif high1 > self._psar.iloc[i]:
                         self._psar.iloc[i] = high1
 
diff --git a/ta/volatility.py b/ta/volatility.py
index 3bbf57e..bf994db 100644
--- a/ta/volatility.py
+++ b/ta/volatility.py
@@ -47,7 +47,7 @@ def _run(self):
         close_shift = self._close.shift(1)
         true_range = self._true_range(self._high, self._low, close_shift)
         atr = np.zeros(len(self._close))
-        atr[self._window - 1] = true_range[0 : self._window].mean()
+        atr[self._window - 1] = true_range[0:self._window].mean()
         for i in range(self._window, len(atr)):
             atr[i] = (atr[i - 1] * (self._window - 1) + true_range.iloc[i]) / float(
                 self._window