<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def as_percent(precision=2, **kwargs):
 """Convert number to percentage string. Parameters: :param v: numerical value to be converted :param precision: int decimal places to round to """

    if not isinstance(precision, Integral):
        raise TypeError("Precision must be an integer.")

    return _surpress_formatting_errors(
        _format_numer(".{}%".format(precision))
    )