input: Write a function to convert a list of tuples into a dictionary.
  assert list_to_dict([('a', 1), ('b', 2), ('c', 3)]) == {'a': 1, 'b': 2, 'c': 3}
  assert list_to_dict([(1, 'one'), (2, 'two'), (3, 'three')]) == {1: 'one', 2: 'two', 3: 'three'}
  assert list_to_dict([]) == {}
output: def list_to_dict(lst):
      return dict(lst)