/usr/lib/python2.7/dist-packages/sage/graphs/ is in sagemath-common 8.1-7ubuntu1.
This file is owned by root:root, with mode 0o755.
..
/usr/lib/python2.7/dist-packages/sage/graphs/__init__.py
/usr/lib/python2.7/dist-packages/sage/graphs/all.py
/usr/lib/python2.7/dist-packages/sage/graphs/base/
/usr/lib/python2.7/dist-packages/sage/graphs/base/__init__.py
/usr/lib/python2.7/dist-packages/sage/graphs/base/boost_graph.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/base/c_graph.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/base/dense_graph.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/base/graph_backends.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/base/overview.py
/usr/lib/python2.7/dist-packages/sage/graphs/base/sparse_graph.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/base/static_dense_graph.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/base/static_sparse_backend.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/base/static_sparse_graph.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/bipartite_graph.py
/usr/lib/python2.7/dist-packages/sage/graphs/cliquer.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/convexity_properties.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/digraph.py
/usr/lib/python2.7/dist-packages/sage/graphs/digraph_generators.py
/usr/lib/python2.7/dist-packages/sage/graphs/distances_all_pairs.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/dot2tex_utils.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/
/usr/lib/python2.7/dist-packages/sage/graphs/generators/__init__.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/basic.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/chessboard.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/classical_geometries.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/degree_sequence.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/families.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/intersection.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/platonic_solids.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/random.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/smallgraphs.py
/usr/lib/python2.7/dist-packages/sage/graphs/generators/world_map.py
/usr/lib/python2.7/dist-packages/sage/graphs/generic_graph.py
/usr/lib/python2.7/dist-packages/sage/graphs/generic_graph_pyx.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/graph.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_coloring.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_database.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_decompositions/
/usr/lib/python2.7/dist-packages/sage/graphs/graph_decompositions/__init__.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_decompositions/fast_digraph.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/graph_decompositions/rankwidth.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/graph_decompositions/vertex_separation.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/graph_editor.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_generators.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_input.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_latex.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_list.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_plot.py
/usr/lib/python2.7/dist-packages/sage/graphs/graph_plot_js.py
/usr/lib/python2.7/dist-packages/sage/graphs/hypergraph_generators.py
/usr/lib/python2.7/dist-packages/sage/graphs/independent_sets.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/isgci.py
/usr/lib/python2.7/dist-packages/sage/graphs/line_graph.py
/usr/lib/python2.7/dist-packages/sage/graphs/linearextensions.py
/usr/lib/python2.7/dist-packages/sage/graphs/lovasz_theta.py
/usr/lib/python2.7/dist-packages/sage/graphs/mcqd.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/modular_decomposition.py
/usr/lib/python2.7/dist-packages/sage/graphs/orientations.py
/usr/lib/python2.7/dist-packages/sage/graphs/partial_cube.py
/usr/lib/python2.7/dist-packages/sage/graphs/pq_trees.py
/usr/lib/python2.7/dist-packages/sage/graphs/print_graphs.py
/usr/lib/python2.7/dist-packages/sage/graphs/schnyder.py
/usr/lib/python2.7/dist-packages/sage/graphs/trees.pxd
/usr/lib/python2.7/dist-packages/sage/graphs/tutte_polynomial.py