Using literal_eval is not needed (and it is not good idea - when you want to evaluate something answer is don't do it). Just use something from below code:
our_dict[key] = value
# for example in list comprehension
our_dict = {value: count for count, value in enumerate(['a', 'b', 'c', 'd'])}
print(our_dict)
# > {'a': 0, 'b': 1, 'c': 2, 'd': 3}