text: from pymongo import MongoClient
  import pandas as pd
  
  def convert_db_to_df(db_name, collection_name, host='localhost', address=27017):
      """ Returns a dataframe given a database name and collection name.
  
          Args:
              db_name (str): name of database
              collection_name (str): name of collection
              host (str): 'localhost' (default) for mongodb on local computer
              address (int): '27017' (default) for mongodb on local computer
  
          Returns:
              df (pandas dataframe)
      """
  
      client = MongoClient(host, address)
      db = client[db_name]
      c = db[collection_name]
      df = pd.DataFrame(list(c.find()))
      return df
  
  def get_db_names(host='localhost', address=27017):
      """ Returns a list of names of the databases available at the provided address.
  
          Args:
              host (str): 'localhost' (default) for mongodb on local computer
              address (int): '27017' (default) for mongodb on local computer
  
          Returns:
              list of database names
      """
  
      client = MongoClient(host, address)
      return client.database_names()
  
  def get_collection_names(db_name, host='localhost', address=27017):
      """ Returns a list of the names of the collections at the specified database.
  
          Args:
              db_name (str): name of database
              host (str): 'localhost' (default) for mongodb on local computer
              address (int): '27017' (default) for mongodb on local computer
  
          Returns:
              list of collections names
      """
      client = MongoClient(host, address)
      db = client[db_name]
      return db.collection_names()
  