input: Write a function to check if an element exists within a given list of integers. If the element exists, return True; otherwise, return False.
  assert element_exists(5, [1, 2, 3, 4, 5])==True
  assert element_exists(10, [1, 2, 3, 4, 5])==False
  assert element_exists(0, [-1, -2, -3, 0, -4])==True
  assert element_exists(-5, [1, 2, 3, 4, 5])==False
output: def element_exists(element, lst):
      return element in lst