checking value in dictionary python code example

Example 1: python check if value exists in any key

>>> d = {'1': 'one', '3': 'three', '2': 'two', '5': 'five', '4': 'four'}
>>> 'one' in d.values()
True

Example 2: how to know if a key is in a dictionary python

dict = {"key1": 1, "key2": 2}

if "key1" in dict: