code: def full_name(self):
          
          if not self.name:
              raise ValueError("Missing variable name.")
          return "%s/variables/%s" % (self.config.full_name, self.name)
docs: Fully-qualified name of this variable.
  
          Example:
          ``projects/my-project/configs/my-config/variables/my-var``
  
          :rtype: str
          :returns: The full name based on config and variable names.
  
          :raises: :class:`ValueError` if the variable is missing a name.