input: Write a function to check if an element exists within a given list of integers. Return True if the element exists and False otherwise.
  assert element_exists(3, [1, 2, 3, 4, 5])==True
  assert element_exists(6, [1, 2, 3, 4, 5])==False
  assert element_exists(0, [])==False
  assert element_exists('a', [1, 2, 3, 'a', 4, 5])==True
  assert element_exists(None, [None, 1, 2, 3, 4, 5])==True
output: def element_exists(element, lst):
      return element in lst