Setter for **self.__default_project** attribute.

        :param value: Attribute value.
        :type value: unicode

def default_project(self, value):
        """
        Setter for **self.__default_project** attribute.

        :param value: Attribute value.
        :type value: unicode
        """

        if value is not None:
            assert type(value) is unicode, \
                "'{0}' attribute: '{1}' type is not 'unicode'!".format("default_project", value)
        self.__default_project = value