## Example: Simple db manager class with context manager
class MyDBManager:
  def __init__(self):
      # our dummy database
      self.some_db = {"id": [], "name": []}

  # this method is called when entering the 'with' statement
  def __enter__(self):
      return self

  # this method is called when exiting the 'with' block code
  def __exit__(self, exc_type, exc_val, exc_tb):
      # here we are clearing the database when exiting
      self.some_db["id"] = []
      self.some_db["name"] = []

  # a function to add values to our db
  def add(self, my_id, name):
      self.some_db["id"].append(my_id)
      self.some_db["name"].append(name)


# create a instance of our db class
db = MyDBManager()

# using the 'with' on our instance
with db as db_handler:
  # add some values to our db
  db_handler.add(3251, "bob")
  db_handler.add(3252, "rob")
  db_handler.add(3253, "job")
  db_handler.add(3251, "tob")
  # print the db data
  print(db_handler.some_db)  # {'id': [3251, 3252, 3253, 3251], \
                              # 'name': ['bob', 'rob', 'job', 'tob']}
  # now to clear the db just get out of the indentation

# check the data in db
print(db.some_db)  # {'id': [], 'name': []}
# as soon as we were out of the indentation, '__exit__()'
# was called automatically which cleared the data, try modifying this
# behaviour to remove duplicate entries