Let's suppose that I have a nested dictionary which looks like that:

parent_dict = { 'parent_key': {'child_key': 'child_value'}

How can I write the following code:

if parent_dict.get('parent_key') is not None and parent_dict['parent_key']['child_key']=='value_1':print('Value detected')

in a more efficient way in terms of readability and amount of code?

Specifically I think that the first if condition could be somehow integrated with the second one in one condition.

So for I would like it to be like that:

if condition_x:print('Value detected')

where condition_x checks both if the parent dict is not empty and if not then it returns the value of the child dict otherwise it returns None.

you could use the dict.get method:

if parent_dict.get('parent_key', {}).get('child_key') == 'value_1':...

dict.get(key) will return dict[key] if the key exists; otherwise it will return None.dict.get(key, default) will return default if the key does not exist. setting the default value to an empty dict {} will make the second .get work.