code: def expand_defaults(self, client=False, getenv=True, getshell=True):
          
          if not isinstance(self._default, six.string_types):
              self.expanded_default = self._default
          else:
              self.expanded_default = coerce(self.type, expand_defaults(
                  self._default, client, getenv, getshell))
docs: Compile env, client_env, shell and client_shell commands