code: async def fetch_block(self, request):
          
          error_traps = [error_handlers.BlockNotFoundTrap]
  
          block_id = request.match_info.get('block_id', '')
          self._validate_id(block_id)
  
          response = await self._query_validator(
              Message.CLIENT_BLOCK_GET_BY_ID_REQUEST,
              client_block_pb2.ClientBlockGetResponse,
              client_block_pb2.ClientBlockGetByIdRequest(block_id=block_id),
              error_traps)
  
          return self._wrap_response(
              request,
              data=self._expand_block(response['block']),
              metadata=self._get_metadata(request, response))
docs: Fetches a specific block from the validator, specified by id.
          Request:
              path:
                  - block_id: The 128-character id of the block to be fetched
  
          Response:
              data: A JSON object with the data from the fully expanded Block
              link: The link to this exact query