def calculate_dependencies(self):
        # Normal deps first
        for migration in self._get_dependency_objects("depends_on"):
            self.dependencies.add(migration)
            migration.dependents.add(self)
        # And reverse deps
        for migration in self._get_dependency_objects("needed_by"):
            self.dependents.add(migration)
            migration.dependencies.add(self)
        # And implicit ordering deps
        previous = self.previous()
        if previous:
            self.dependencies.add(previous)
            previous.dependents.add(self)
Loads dependency info for this migration, and stores it in itself
dataset/ETHPy150Open cloudera/hue/desktop/core/ext-py/South-1.0.2/south/migration/base.py/Migration.calculate_dependencies