importmatplotlib.pyplotaspltimportmatplotlibplt.figure(figsize=(6,5))plt.plot(range(11),color="0.9")msg= (r"Normal Text. $Text\ in\ math\ mode:\ "r"\int_{0}^{\infty } x^2 dx$")plt.text(1,7,msg,size=12,font='Arial')# math_fontfamily='cm'plt.show()

.... File "c:\repos\matplotlib\matplotlib\lib\matplotlib\mathtext.py", line 431, in _parse_cached    else _api.check_getitem(  File "c:\repos\matplotlib\matplotlib\lib\matplotlib\_api\__init__.py", line 187, in check_getitem    raise ValueError(ValueError: None is not a valid value for fontset; supported values are 'cm', 'dejavuserif', 'dejavusans', 'stix', 'stixsans', 'custom'