Restrict input type to the positive integers (1, 2, 3...)

def positive(value, argument='argument'):
    """ Restrict input type to the positive integers (1, 2, 3...) """
    value = _get_integer(value)
    if value < 1:
        error = ('Invalid {arg}: {value}. {arg} must be a positive '
                 'integer'.format(arg=argument, value=value))
        raise ValueError(error)
    return value