<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _validate_frow(self, frow):
 """Validate frow argument."""

        is_int = isinstance(frow, int) and (not isinstance(frow, bool))
        pexdoc.exh.addai("frow", not (is_int and (frow >= 0)))
        return frow