input: Write a python function to fetch records from a MongoDB collection.
  assert isinstance(fetchRecords('localhost', 27017, 'mydatabase', 'mycollection'), pymongo.cursor.Cursor)
  assert isinstance(fetchRecords('localhost', 27017, 'testdb', 'testcollection'), pymongo.cursor.Cursor)
  assert isinstance(fetchRecords('127.0.0.1', 27017, 'exampledb', 'examplecollection'), pymongo.cursor.Cursor)
output: def fetchRecords(host, port, database, collection):
      from pymongo import MongoClient
      client = MongoClient(host, port)
      db = client[database]
      return db[collection].find()