input: Write a function to delete a given key from a dictionary. The function should modify the dictionary in-place and return None.
  def delete_key(dic, k):
    if k in dic:
      del dic[k]
  
  dictionary = {'foo': 1, 'bar': 2, 'baz': 3}
  key = 'baz'
  
  delete_key(dictionary, key)
  
  assert dictionary == {'foo': 1, 'bar': 2}
  assert delete_key({'a': 1, 'b': 2}, 'c') == None
  assert delete_key({}, 'c') == None
  assert delete_key({'a': 1, 'b': 2}, 'a') == None
  assert delete_key({'a': 1, 'b': 2}, 'b') == None
output: def delete_key(dic, k):
    if k in dic:
      del dic[k]