from typing import OrderedDict
import copy


def subtract_model_states(minuend: OrderedDict,
                          subtrahend: OrderedDict) -> OrderedDict:
    """
    Returns difference of two model_states: minuend - subtrahend
    """
    result_state = copy.deepcopy(minuend)
    for key, w in subtrahend.items():
        result_state[key] -= w
    return result_state