rename `required_fields` to `fields`

src/plot.py

@@ -223,10 +223,10 @@ def _check_extra_class_fields(
 def _check_class_fields(
     obj: Dict[str, Any],
     name: str,
-    required_fields: Dict[str, bool],
+    fields: Dict[str, bool],
     sub_path: List[str] = None
 ):
-    for f, is_optional in required_fields.items():
+    for f, is_optional in fields.items():
         if not is_optional and not f in obj.keys():
             full_path = '.'.join(sub_path + [f]) if sub_path is not None else f
             panic(
@@ -234,7 +234,7 @@ def _check_class_fields(
                 f"missing required field '{full_path}' in {name}",
             )
 
-    _check_extra_class_fields(obj, name, required_fields, sub_path=sub_path)
+    _check_extra_class_fields(obj, name, fields, sub_path=sub_path)
 
 
 def check(graphs: Any):
@@ -246,8 +246,8 @@ def check(graphs: Any):
             f"input is not a list, found {type(graphs).__name__}",
         )
 
-    required_graph_fields = __get_class_fields(Graph)
-    required_point_fields = __get_class_fields(Point)
+    graph_fields = __get_class_fields(Graph)
+    point_fields = __get_class_fields(Point)
 
     for i, g in enumerate(graphs):
         debug(f"checking graph {i}")
@@ -259,11 +259,11 @@ def check(graphs: Any):
 
         name = g.get('name', i)
 
-        _check_class_fields(g, f"graph {name}", required_graph_fields)
+        _check_class_fields(g, f"graph {name}", graph_fields)
 
         for j, p in enumerate(g["points"]):
             _check_class_fields(
-                p, f"graph {name}", required_point_fields, sub_path=["points", str(j)]
+                p, f"graph {name}", point_fields, sub_path=["points", str(j)]
             )
 
         # TODO: check style