def environment_does_base_variable_exist(self, name):
        """Checks if the given environment variable exists in the session's base
        environment (:py:func:`IGuestSession.environment_base` ).

        in name of type str
            Name of the environment variable to look for.  This cannot be
            empty nor can it contain any equal signs.

        return exists of type bool
            TRUE if the variable exists, FALSE if not.

        raises :class:`VBoxErrorNotSupported`
            If the guest additions does not
support the session base environment feature.  Support for this was
introduced with protocol version XXXX.
        
        raises :class:`VBoxErrorInvalidObjectState`
            If the guest additions has
yet to report the session base environment.
        
        """
        if not isinstance(name, basestring):
            raise TypeError("name can only be an instance of type basestring")
        exists = self._call("environmentDoesBaseVariableExist",
                     in_p=[name])
        return exists