human
Complete the below
def _groups_or_na_fun(regex):

    ''''Used in both extract_noexpand and extract_frame'
    '''
 Can you provide a the Python code you requested?
assistant
#Here is the Python code you requested.
    if (regex.groups == 0):
        raise ValueError('pattern    contains    no    capture    groups')
    empty_row = ([np.nan] * regex.groups)
    def f(x):
        if (not isinstance(x, compat.string_types)):
            return empty_row
        m = regex.search(x)
        if m:
            return [(np.nan if (item is None) else item) for item in m.groups()]
        else:
            return empty_row
    return f