input: Write a function that creates an instance of the "sru" class and calls its "search" method with a specified query string, a collection name, start record number, maximum number of records to return, and record schema. The function should return the search results by accessing the properties of the "response" object.
  
  
  def search_kb_sru(query, collection, startrecord=1, maximumrecords=1, recordschema=None):
      sru_instance = sru()
      response_obj = sru_instance.search(query, collection, startrecord, maximumrecords, recordschema)
      if response_obj:
          return {
              'titles': response_obj.titles,
              'creators': response_obj.creators,
              'subjects': response_obj.subjectsBrinkman
          }
      return None
  
  assert search_kb_sru("search term", "ANP") is not None
  assert search_kb_sru("another search", "GGC", maximumrecords=3) is not None
  assert search_kb_sru("query with no results", "BYVANCK") is None
  assert search_kb_sru("specific query", "SGD", startrecord=2, maximumrecords=2) is not None
  
output: 
  def search_kb_sru(query, collection, startrecord=1, maximumrecords=1, recordschema=None):
      sru_instance = sru()
      response_obj = sru_instance.search(query, collection, startrecord, maximumrecords, recordschema)
      if response_obj:
          return {
              'titles': response_obj.titles,
              'creators': response_obj.creators,
              'subjects': response_obj.subjectsBrinkman
          }
      return None
  