def METHOD_NAME(shell_type):
    if abs(shell_type) == 0:
        return {0: 0}
    elif abs(shell_type) == 1:
        return {0: 0, 1: 0, 2: 0}
    elif abs(shell_type) == 2:
        return {0: 0, 1: 0, 2: 0, 3: 0, 4: 0, 5: 0}
    else:
        raise KeyError("only s, p, d shell is allowed.")