code: def getblockhash(self, blocknum: int) -> str:
          '''get blockhash'''
  
          query = 'getblockhash' + '&height=' + str(blocknum)
          return cast(str, self.api_req(query)f getblockhash(self, blocknum: int) -> str:
          '''get blockhash'''
  
          query = 'getblockhash' + '&height=' + str(blocknum)
          return cast(str, self.api_req(query))
docs: get blockhash