:param string mask: Add this mask, prefix with ``!`` to exclude this mask from matching.
:param table masks: Adds the keys of the table to the :class:`NetmaskGroup`. It should be a table whose keys are :class:`ComboAddress` objects and whose values are integers. The integer values of the table entries are ignored. The table is of the same type as the table returned by the `exceed*` functions.
- .. method:: addNMG(otherNMGL NetmaskGroup)
+ .. method:: addNMG(otherNMG: NetmaskGroup)
.. versionadded:: 1.9.0