def add_distribution(self, distribution):
        """Add the *distribution* to the graph.

        :type distribution: :class:`distutils2.database.InstalledDistribution`
                            or :class:`distutils2.database.EggInfoDistribution`
        """
        self.adjacency_list[distribution] = []
        self.reverse_list[distribution] = []
        #self.missing[distribution] = []
Add the *distribution* to the graph.

        :type distribution: :class:`distutils2.database.InstalledDistribution`
                            or :class:`distutils2.database.EggInfoDistribution`
        
product/gradle-plugin/src/main/python/pip/_vendor/distlib/database.py