how can i chcek whether there is key or not to dictionary python code example

Example 1: python check if key exists

# You can use 'in' on a dictionary to check if a key exists
d = {"key1": 10, "key2": 23}
"key1" in d
# Output:
# True

Example 2: python check if value exists in any key

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