human
Complete the below
def _process_limits(func, limits):

    ''''Limits should be of the form (x, start, stop).
    x should be a symbol. Both start and stop should be bounded.
    * If x is not given, x is determined from func.
    * If limits is None. Limit of the form (x, -pi, pi) is returned.
    Examples
    >>> from sympy import pi
    >>> from sympy.series.fourier import _process_limits as pari
    >>> from sympy.abc import x
    >>> pari(x**2, (x, -2, 2))
    (x, -2, 2)
    >>> pari(x**2, (-2, 2))
    (x, -2, 2)
    >>> pari(x**2, None)
    (x, -pi, pi)'
    '''

Can you provide a the Python program you requested?
assistant
#Here is the Python program you requested.
    def _find_x(func):
        free = func.free_symbols
        if (len(func.free_symbols) == 1):
            return free.pop()
        elif (len(func.free_symbols) == 0):
            return Dummy('k')
        else:
            raise ValueError(('    specify    dummy    variables    for    %s.    If    the    function    contains    more    than    one    free    symbol,    a    dummy    variable    should    be    supplied    explicitly    e.g.    FourierSeries(m*n**2,    (n,    -pi,    pi))' % func))
    (x, start, stop) = (None, None, None)
    if (limits is None):
        (x, start, stop) = (_find_x(func), (- pi), pi)
    if is_sequence(limits, Tuple):
        if (len(limits) == 3):
            (x, start, stop) = limits
        elif (len(limits) == 2):
            x = _find_x(func)
            (start, stop) = limits
    if ((not isinstance(x, Symbol)) or (start is None) or (stop is None)):
        raise ValueError(('Invalid    limits    given:    %s' % str(limits)))
    unbounded = [S.NegativeInfinity, S.Infinity]
    if ((start in unbounded) or (stop in unbounded)):
        raise ValueError('Both    the    start    and    end    value    should    be    bounded')
    return sympify((x, start, stop))