input: Write a python function to check if all values in a dictionary are True.
  assert all_dict_values_true({'a': True, 'b': True, 'c': True}) == True
  assert all_dict_values_true({'a': True, 'b': False, 'c': True}) == False
  assert all_dict_values_true({'a': 1, 'b': 2, 'c': 0}) == False
output: def all_dict_values_true(d):
      return all(d.values())