db = MongoDB('CONNECTION_STRING', database='mydb', collection='mycollection') #Use as Python dictionary

mongodb.py

from pymongo import MongoClient

class MongoDB():

	def __init__(self, connectionString, database, collection):
		self._client = MongoClient(connectionString)
		self._db = self._client[database]
		self._col = self._db[collection]

	def __setitem__(self, key, value):
		self._col.update_one({'_id': key}, {"$set": {'_id': key, 'value': value}}, upsert=True)
	
	def __getitem__(self, key):
		result = self._col.find_one({'_id': key})

		if not result:
			raise KeyError(key)
		else:
			return result['value']

	def __delitem__(self, key):
		result = self._col.delete_one({'_id': key})

		if result.deleted_count == 0:
			raise KeyError(key)
	
	def __len__(self):
		return self._col.count_documents({})
	
	def __iter__(self):
		return (item['_id'] for item in self._col.find({}))

	def __contains__(self, key):
		result = self._col.find_one({'_id': key})

		if not result:
			return False
		else:
			return True