get_occurrence, nested_delete, nested_update is not working for keys having values 'False' or 0

Created by: rameshrvr

Example:

>>> import nested_lookup
>>> 
>>> data = {
...             "hardware_details": {
...                 "model_name": 'MacBook Pro',
...                 "total_number_of_cores": 0,
...                 "memory": False
...             }
...         }
>>> 
>>> nested_lookup.nested_update(data, key='total_number_of_cores', value=5)
{'hardware_details': {'model_name': 'MacBook Pro', 'total_number_of_cores': 0, 'memory': False}}
>>> nested_lookup.nested_delete(data, 'memory')
{'hardware_details': {'model_name': 'MacBook Pro', 'total_number_of_cores': 0, 'memory': False}}
>>> 
>>> nested_lookup.get_occurrence_of_key(data, key='total_number_of_cores')
0

Operations are skipped since data.get(key) returned false.