def __init__(self, Atom, ShellFn):
    self.Atom = Atom
    self.Fn = ShellFn
    assert isinstance(self.Fn, FBasisShell)
def __init__(self, Atom, ShellFn):
    self.Atom = Atom
    self.Fn = ShellFn
    assert isinstance(self.Fn, FBasisShell)