code: def get(self, key):
          
          self._get_table()
          s = self.table.get_item(key=key)
          log.debug("Retrieved from key '%s' the object: '%s'" % (key, s['value']))
          return self.from_string(s['value'])
docs: Get the string representation of the object stored in DynamoDB under this key,
          convert it back to an object using the 'from_string' unmarshalling method passed
          in the constructor and return the object. Return None if no object found.