Checks if all components are opened.

        To be checked components must implement [[IOpenable]] interface.
        If they don't the call to this method returns true.

        :param components: a list of components that are to be checked.

        :return: true if all components are opened and false if at least one component is closed.

def is_opened(components):
        """
        Checks if all components are opened.

        To be checked components must implement [[IOpenable]] interface.
        If they don't the call to this method returns true.

        :param components: a list of components that are to be checked.

        :return: true if all components are opened and false if at least one component is closed.
        """
        if components == None:
            return True

        result = True
        for component in components:
            result = result and Opener.is_opened_one(component)

        return result