human
Complete the below
def TR13(rv):

    ''''Change products of ``tan`` or ``cot``.
    Examples
    >>> from sympy.simplify.fu import TR13
    >>> from sympy import tan, cot, cos
    >>> TR13(tan(3)*tan(2))
    -tan(2)/tan(5) - tan(3)/tan(5) + 1
    >>> TR13(cot(3)*cot(2))
    cot(2)*cot(5) + 1 + cot(3)*cot(5)'
    '''

Give me a the Python code you requested?
assistant
#Here is the Python code you requested.
    def f(rv):
        if (not rv.is_Mul):
            return rv
        args = {tan: [], cot: [], None: []}
        for a in ordered(Mul.make_args(rv)):
            if (a.func in (tan, cot)):
                args[a.func].append(a.args[0])
            else:
                args[None].append(a)
        t = args[tan]
        c = args[cot]
        if ((len(t) < 2) and (len(c) < 2)):
            return rv
        args = args[None]
        while (len(t) > 1):
            t1 = t.pop()
            t2 = t.pop()
            args.append((1 - ((tan(t1) / tan((t1 + t2))) + (tan(t2) / tan((t1 + t2))))))
        if t:
            args.append(tan(t.pop()))
        while (len(c) > 1):
            t1 = c.pop()
            t2 = c.pop()
            args.append(((1 + (cot(t1) * cot((t1 + t2)))) + (cot(t2) * cot((t1 + t2)))))
        if c:
            args.append(cot(c.pop()))
        return Mul(*args)
    return bottom_up(rv, f)