An exception occurs when using parseMath!The attribute "mathvariant" is incorrect!

[masx200]

<script src="https://cdn.jsdelivr.net/gh/asciimath/asciimathml@master/ASCIIMathML.min.js"></script>

console.log(asciimath.parseMath('sum_(i=1)^n i^3=((n(n+1))/2)^2'))

<math title="sum_(i=1)^n i^3=((n(n+1))/2)^2"><mstyle mathcolor="blue" fontsize="1em" mathsize="1em" fontfamily="serif" mathvariant="serif" displaystyle="true"><mi>s</mi><mi>u</mi><mi>m</mi><mo>_</mo><mo>(</mo><mi>i</mi><mo>=</mo><mn>1</mn><mo>)</mo><mo>^</mo><mi>n</mi><mi>i</mi><mo>^</mo><mn>3</mn><mo>=</mo><mo>(</mo><mo>(</mo><mi>n</mi><mo>(</mo><mi>n</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>)</mo><mo>/</mo><mn>2</mn><mo>)</mo><mo>^</mo><mn>2</mn></mstyle></math>

The attribute "mathvariant" is incorrect! "serif"

https://developer.mozilla.org/en-US/docs/Web/MathML/Element/mi

mathvariant
This logical class of the identifier, which varies in typography. That is, although the names suggest the typographic style for the class, semantically, items with the same class are treated "the same" within an expression, which might or might not involve displaying them with the named typography. The following values are allowed:
normal (Default value for more than one character) ; Example
bold ; Example
italic (Default value for a single character) ; Example
bold-italic ; Example
double-struck ; Example
bold-fraktur ; Example
script ; Example
bold-script ; Example
fraktur ; Example
sans-serif ; Example
bold-sans-serif ; Example
sans-serif-italic ; Example
sans-serif-bold-italic ; Example
monospace ; Example
initial ; مثال
tailed ; مثال
looped ; مثال
stretched ; مثال

[masx200]

The way it transforms is obviously wrong!