human
Solve the following python programming problem given the following code:
def _separate_sq(p) : 
    '
    helper function for ``_minimal_polynomial_sq``

    It selects a rational ``g`` such that the polynomial ``p``
    consists of a sum of terms whose surds squared have gcd equal to ``g``
    and a sum of terms with surds squared prime with ``g``;
    then it takes the field norm to eliminate ``sqrt(g)``

    See simplify.simplify.split_surds and polytools.sqf_norm.

    Examples
    ========

    >>> from sympy import sqrt
    >>> from sympy.abc import x
    >>> from sympy.polys.numberfields import _separate_sq
    >>> p= -x + sqrt(2) + sqrt(3) + sqrt(7)
    >>> p = _separate_sq(p).
p
    -x**2 + 2*sqrt(3)*x + 2*sqrt(7)*x - 2*sqrt(21) - 8
    >>> p = _separate_sq(p).
p
    -x**4 + 4*sqrt(7)*x**3 - 32*x**2 + 8*sqrt(7)*x + 20
    >>> p = _separate_sq(p).
p
    -x**8 + 48*x**6 - 536*x**4 + 1728*x**2 - 400

    ' 
    from sympy.utilities.iterables import sift 
    def is_sqrt(expr) : 
        return (expr.is_Pow and (expr.exp is S.Half)) 
a = [] 
    for y in p.args : 
        if (not y.is_Mul) : 
            if is_sqrt (y) : 
                a.append ((S.One, (y ** 2))) 
else : 
                if y.is_Atom : 
                    a.append ((y, S.One)) 
else : 
                    if (y.is_Pow and y.exp.is_integer) : 
                        a.append ((y, S.One)) 
else : 
                        raise NotImplementedError 
continue 
sifted = sift (y.args, is_sqrt) 
        a.append ((Mul (* p [False]), (Mul (* sifted [True]) ** 2))) 
a.sort (key = (lambda z : z [1])) 
    if (a [(- 1)] [1] is S.One) : 
        return p 
surds = [z for (y, z) in a] 
    for i in range (len (surds)) : 
        if (surds [i] != 1) : 
            break 
(g, b1, b2) = _split_gcd (* surds [i :]) 
    a1 = [] 
    a2 = [] 
    for (y, z) in a : 
        if (z in b1) : 
            a1.append ((y * (z ** S.Half))) 
else : 
            a2.append ((y * (z ** S.Half))) 
p1 = Add (* a1) 
    p2 = Add (* a2) 
    p = (_mexpand ((p1 ** 2)) - _mexpand ((p2 ** 2))) 
    return p 

    
    

    Fix the buggy line: a.append ((Mul (* p [False]), (Mul (* sifted [True]) ** 2)))
assistant
#Here is Python code to fix the buggy line: a.

a.append ((Mul (* sifted [False]), (Mul (* sifted [True]) ** 2)))