<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_cum_func_with_skipna(skipna, args, kwargs, name):
 """ If this function is called via the 'numpy' library, the third parameter in its signature is 'dtype', which takes either a 'numpy' dtype or 'None', so check if the 'skipna' parameter is a boolean or not """

    if not is_bool(skipna):
        args = (skipna,) + args
        skipna = True

    validate_cum_func(args, kwargs, fname=name)
    return skipna