input: Write a python function to insert an element at a specified position in a list.
  assert insert_element([1, 3, 7, 8], 2, 5) == [1, 3, 5, 7, 8]
  assert insert_element([10, 20, 30, 40], 1, 15) == [10, 15, 20, 30, 40]
  assert insert_element(['a', 'b', 'd'], 2, 'c') == ['a', 'b', 'c', 'd']
output: def insert_element(lst, index, element):
      lst.insert(index, element)
      return lst