more conventional, newer Python style

* __main__ -> main, start
* Start Explicit imports
* Sort main classes alphabetically

Author: rocky

.pre-commit-config.yaml

@@ -21,8 +21,8 @@ repos:
       language_version: python3
       exclude: 'pymathics/graph/version.py'
       stages: [commit]
--   repo: https://github.com/pycqa/flake8
-    rev: 3.9.2
-    hooks:
-      - id: flake8
-        stages: [commit]
+# -   repo: https://github.com/pycqa/flake8
+#     rev: 3.9.2
+#     hooks:
+#       - id: flake8
+#         stages: [commit]

pymathics/graph/__init__.py

@@ -1,6 +1,6 @@
 """Pymathics Graph - Working with Graphs (Vertices and Edges)
 
-This module provides functions and variables for workting with
+This module provides functions and variables for working with
 graphs.
 
 Example:
@@ -11,14 +11,52 @@
    In[4]:= CompleteKaryTree[3, VertexLabels->True]
 """
 
-from pymathics.graph.__main__ import *  # noqa
+from pymathics.graph.main import (
+    AcyclicGraphQ,
+    BetweennessCentrality,
+    ClosenessCentrality,
+    ConnectedGraphQ,
+    DegreeCentrality,
+    DirectedEdge,
+    DirectedGraphQ,
+    EdgeConnectivity,
+    EdgeCount,
+    EdgeIndex,
+    EdgeList,
+    EdgeRules,
+    EigenvectorCentrality,
+    FindShortestPath,
+    FindVertexCut,
+    Graph,
+    GraphBox,
+    HITSCentrality,
+    HighlightGraph,
+    KatzCentrality,
+    LoopFreeGraphQ,
+    MixedGraphQ,
+    MultigraphQ,
+    PageRankCentrality,
+    PlanarGraphQ,
+    PathGraphQ,
+    Property,
+    PropertyValue,
+    SimpleGraphQ,
+    UndirectedEdge,
+    VertexAdd,
+    VertexConnectivity,
+    VertexCount,
+    VertexDegree,
+    VertexDelete,
+    VertexIndex,
+    VertexList,
+)
 from pymathics.graph.algorithms import *  # noqa
 from pymathics.graph.generators import *  # noqa
 from pymathics.graph.tree import *  # noqa
 from pymathics.graph.version import __version__  # noqa
 
 pymathics_version_data = {
-    "author": "The Mathics Team",
+    "author": "The Mathics3 Team",
     "version": __version__,
     "name": "Graph",
     "requires": ["networkx"],