def add_flex_arithmetic_methods(cls):
flex_arith_method, flex_comp_method, _, _, _ = _get_method_wrappers(cls)<EOL>new_methods = _create_methods(cls, flex_arith_method,<EOL>flex_comp_method, bool_method=None,<EOL>special=False)<EOL>new_methods.update(dict(multiply=new_methods['<STR_LIT>'],<EOL>subtract=new_methods['<STR_LIT>'],<EOL>divide=new_methods['<STR_LIT>']))<EOL>assert not any(kname in new_methods for kname in ('<STR_LIT>', '<STR_LIT>', '<STR_LIT>'))<EOL>add_methods(cls, new_methods=new_methods)<EOL>
Adds the full suite of flex arithmetic methods (``pow``, ``mul``, ``add``)
to the class.

Parameters
----------
cls : class
    flex methods will be defined and pinned to this class