human
Complete the below
def TR14(rv, first=True):

    ''''Convert factored powers of sin and cos identities into simpler
    expressions.
    Examples
    >>> from sympy.simplify.fu import TR14
    >>> from sympy.abc import x, y
    >>> from sympy import cos, sin
    >>> TR14((cos(x) - 1)*(cos(x) + 1))
    -sin(x)**2
    >>> TR14((sin(x) - 1)*(sin(x) + 1))
    -cos(x)**2
    >>> p1 = (cos(x) + 1)*(cos(x) - 1)
    >>> p2 = (cos(y) - 1)*2*(cos(y) + 1)
    >>> p3 = (3*(cos(y) - 1))*(3*(cos(y) + 1))
    >>> TR14(p1*p2*p3*(x - 1))
    -18*(x - 1)*sin(x)**2*sin(y)**4'
    '''
assistant
#Here is the Python code you requested.
    def f(rv):
        if (not rv.is_Mul):
            return rv
        if first:
            (n, d) = rv.as_numer_denom()
            if (d is not S.One):
                newn = TR14(n, first=False)
                newd = TR14(d, first=False)
                if ((newn != n) or (newd != d)):
                    rv = (newn / newd)
                return rv
        other = []
        process = []
        for a in rv.args:
            if a.is_Pow:
                (b, e) = a.as_base_exp()
                if (not (e.is_integer or b.is_positive)):
                    other.append(a)
                    continue
                a = b
            else:
                e = S.One
            m = as_f_sign_1(a)
            if ((not m) or (m[1].func not in (cos, sin))):
                if (e is S.One):
                    other.append(a)
                else:
                    other.append((a ** e))
                continue
            (g, f, si) = m
            process.append((g, e.is_Number, e, f, si, a))
        process = list(ordered(process))
        nother = len(other)
        keys = (g, t, e, f, si, a) = list(range(6))
        while process:
            A = process.pop(0)
            if process:
                B = process[0]
                if (A[e].is_Number and B[e].is_Number):
                    if (A[f] == B[f]):
                        if (A[si] != B[si]):
                            B = process.pop(0)
                            take = min(A[e], B[e])
                            if (B[e] != take):
                                rem = [B[i] for i in keys]
                                rem[e] -= take
                                process.insert(0, rem)
                            elif (A[e] != take):
                                rem = [A[i] for i in keys]
                                rem[e] -= take
                                process.insert(0, rem)
                            if (A[f].func is cos):
                                t = sin
                            else:
                   ...