def add_ta_alias_to_map(ta_aliases, ta_map):
    """ adds alias to the ta_map. Needs arguments ta_map defaultdict with sets,
    and tuples with two strings in each. Assumes that all threat actors are
    already in the ta_map. """
    for tup in ta_aliases:
        ta1, ta2 = tup
        s = ta_map[ta1]
        s.update(ta_map[ta2])
        for x in s:
            ta_map[x] = s
    return ta_map
