Show equalized double bond if it is connected to terminal atom.

def equalize_terminal_double_bond(mol):
    """Show equalized double bond if it is connected to terminal atom.
    """
    for i, a in mol.atoms_iter():
        if mol.neighbor_count(i) == 1:
            nb = list(mol.neighbors(i).values())[0]
            if nb.order == 2:
                nb.type = 2