def update_modifiers(old_modifiers, new_modifiers):
    'Update modifiers.\n\n    :param dict old_modifiers: old modifiers\n    :param dict old_modifiers: new modifiers\n    :return dict: resulting modifiers\n    '
    modifiers = old_modifiers.copy()
    for (key, value) in new_modifiers.items():
        if (key in old_modifiers):
            if (_TRANSFORMATIONS.get(key) == _list_transform):
                modifiers[key] += value
            elif (_TRANSFORMATIONS.get(key) == _dict_transform):
                modifiers[key].update(value)
            else:
                modifiers[key] = value
        else:
            modifiers[key] = value
    return modifiers
Update modifiers.

:param dict old_modifiers: old modifiers
:param dict old_modifiers: new modifiers
:return dict: resulting modifiers
def update_modifiers(old_modifiers, new_modifiers):
    'Update modifiers.\n\n    :param dict old_modifiers: old modifiers\n    :param dict old_modifiers: new modifiers\n    :return dict: resulting modifiers\n    '
    modifiers = old_modifiers.copy()
    for (key, value) in new_modifiers.items():
        if (key in old_modifiers):
            if (_TRANSFORMATIONS.get(key) == _list_transform):
                modifiers[key] += value
            elif (_TRANSFORMATIONS.get(key) == _dict_transform):
                modifiers[key].update(value)
            else:
                modifiers[key] = value
        else:
            modifiers[key] = value
    return modifiers