input: Write a function to check if an element exists within a given list of integers. Return True if the element is found in the list, otherwise return False. If the list is empty, return False.
  assert element_exists(5,[1,3,5,7])==True
  assert element_exists(2,[1,3,5,7])==False
  assert element_exists(7,[])==False
  assert element_exists(1,[1,3,5,7])==True
output: def element_exists(element, lst):
      return element in lst