input: Write a python function to check if a search term exists in a list.
  assert check_search_term(["apple", "banana", "cherry"], "banana") == {"exists": True}
  assert check_search_term(["apple", "banana", "cherry"], "grape") == {"exists": False}
  assert check_search_term(["dog", "cat", "mouse"], "cat") == {"exists": True}
output: def check_search_term(lst, term):
      return {"exists": term in lst}