'Iterates over the creation operators.
Examples
>>> from sympy import symbols
>>> i, j = symbols(\'i j\', below_fermi=True)
>>> a, b = symbols(\'a b\', above_fermi=True)
>>> from sympy.physics.secondquant import NO, F, Fd
>>> no = NO(Fd(a)*F(i)*F(b)*Fd(j))
>>> no.iter_q_creators()
<generator object... at 0x...>
>>> list(no.iter_q_creators())
[0, 1]
>>> list(no.iter_q_annihilators())
[3, 2]'

def iter_q_creators(self):

    ops = self.args[0].args
    iter = range(0, len(ops))
    for i in iter:
        if ops[i].is_q_creator:
            (yield i)
        else:
            break
