input: Write a function to check if an element exists within a given list of integers. The function should return True if the element is found in the list, otherwise 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(7, [1, 2, 3, 4, 5]) == False
  assert element_exists(0, []) == False
  assert element_exists('a', [1, 'a', 3]) == True
  assert element_exists(3, [3, 3, 3]) == True
output: def element_exists(elem, list_int):
    return elem in list_int