lazysignals._utils
==================

.. py:module:: lazysignals._utils


Classes
-------

.. autoapisummary::

   lazysignals._utils.SingletonMeta


Functions
---------

.. autoapisummary::

   lazysignals._utils.is_added


Module Contents
---------------

.. py:class:: SingletonMeta

   Bases: :py:obj:`type`


   A metaclass for creating singleton classes.

   This metaclass ensures that only one instance of a class is created, and that all subsequent calls to the constructor return the same instance.


   .. py:attribute:: _instances


   .. py:method:: __call__(*args, **kwargs)

      Create and store a new instance of the class if it doesn't exist yet, or return the existing instance.



.. py:function:: is_added(s, x)

   Adds an element to a set and returns if it was not already present.

   :param s: The set to add the element to.
   :param x: The element to add.
   :returns: ``True`` if ``x`` was not in ``s``, ``False`` otherwise.