provides a list of :class:`~stem.util.connection.Connection`. Note that
addresses may be IPv4 *or* IPv6 depending on what the platform supports.

.. versionadded:: 1.1.0

.. versionchanged:: 1.5.0
   Made our resolver argument optional.

.. versionchanged:: 1.5.0
   IPv6 support when resolving via proc, netstat, lsof, or ss.

:param Resolver resolver: method of connection resolution to use, if not
  provided then one is picked from among those that should likely be
  available for the system
:param int process_pid: pid of the process to retrieve
:param str process_name: name of the process to retrieve

:returns: **list** of :class:`~stem.util.connection.Connection` instances

:raises:
  * **ValueError** if neither a process_pid nor process_name is provided

  * **IOError** if no connections are available or resolution fails
    (generally they're indistinguishable). The common causes are the
    command being unavailable or permissions.
r