docs: def get_txn(self, txn_name, txn_uri):
  
  		'''
  		Retrieves known transaction and adds to self.txns.
  
  		TODO:
  			Perhaps this should send a keep-alive request as well?  Obviously still needed, and would reset timer.
  
  		Args:
  			txn_prefix (str, rdflib.term.URIRef): uri of the transaction. e.g. http://localhost:8080/rest/txn:123456789
  			txn_name (str): local, human name for transaction
  
  		Return:
  			(Transaction) local instance of transactions from self.txns[txn_uri]
  		'''
  
  		# parse uri
  		txn_uri = self.parse_uri(txn_uri)
  
  		# request new transaction
  		txn_response = self.api.http_request('GET',txn_uri, data=None, headers=None)
  
  		# if 200, transaction exists
  		if txn_response.status_code == 200:
  			logger.debug("transactoin found: %s" % txn_uri)
  
  			# init new Transaction, and pass Expires header
  			txn = Transaction(
  				self, # pass the repository
  				txn_name,
  				txn_uri,
  				expires = None)
  
  			# append to self
  			self.txns[txn_name] = txn
  
  			# return
  			return txn
  
  		# if 404, transaction does not exist
  		elif txn_response.status_code in [404, 410]:
  			logger.debug("transaction does not exist: %s" % txn_uri)
  			return False
  
  		else:
  			raise Exception('HTTP %s, could not retrieve transaction' % txn_response.status_code)