input: Write a function to check if an element exists within a given list of integers. If it exists return True else return False. If the given list is empty then return False.
  def element_exists(elem, list_int):
    return elem in list_int
  assert element_exists(5, [1, 2, 3, 4, 5])==True
  assert element_exists(6, [1, 2, 3, 4, 5])==False
  assert element_exists(3, [])==False
output: def element_exists(elem, list_int):
    return elem in list_int