Document layout.py with some additional fixes

django_forms_as_jsonschema/layout.py

-import uuid
+"""Re-implementation of django-material's form layout mechanics.
+
+This implementation provides a drop-in replacement for django-material's
+Layout, Row, and Fieldset classes, which allow rendering into a JSON schema.
+
+cf. http://docs.viewflow.io/material_forms.html
+"""
+
 from abc import ABC
 from dataclasses import dataclass
-from typing import Union
+from typing import Optional, Union
 
 from django.utils.text import slugify
 
 
 class LayoutNode(ABC):
+    """Abstract node in a form layout."""
     def __init__(self, *elements):
         self.elements = elements
 
     def build_schema(self, schema, form_fields) -> dict:
+        """Render this node into a JSON schema fragment."""
         props = {}
         for field in self.elements:
             if isinstance(field, LayoutNode):
+                # Recurse and add fragment of the sub-node
                 built_schema = field.build_schema(schema, form_fields)
                 props.update(built_schema["properties"])
             else:
+                # Add verbatim field
                 props[field] = schema.generate_field(form_fields[field])
+
         return {"properties": props}
 
 
 @dataclass
 class _Section:
+    """Visual section in a form."""
     codename: str
     title: str
-    description: str = None
+    description: Optional[str] = None
 
 
 class Row(LayoutNode):
+    """Visual row in a form."""
+
     def build_schema(self, schema, form_fields):
-        row_name = "row-" + str(uuid.uuid4())
+        """Render this row as a JSON schema fragment."""
+        row_name = f"row-{id(self)}"
         fields = super().build_schema(schema, form_fields)["properties"]
         for k in fields.keys():
-            fields[k]["x-options"] = {
-                "fieldColProps": {
-                    "cols": 12,
-                    "md": ""
-                }
-            }
+            # Make row responsive by extending each field to full width on smaller viewports
+            fields[k].setdefault("x-options", {}).setdefault("fieldColProps", {}).update({"cols": 12, "md": ""})
+
         return {
             "properties": {
                 row_name: {
@@ -50,15 +63,18 @@ class Row(LayoutNode):
 
 
 class Fieldset(LayoutNode):
+    """Visual set of fields in a form."""
     def __init__(self, name: Union[tuple[str, str], str], *elements):
         super().__init__(*elements)
         codename = str(slugify(name))
-        if type(name) == tuple:
-            self.section = _Section(codename, *map(str, name))
+
+        if isinstance(name, tuple):
+            self.section = _Section(codename, *name)
         else:
-            self.section = _Section(codename, str(name))
+            self.section = _Section(codename, name)
 
     def build_schema(self, schema, form_fields) -> dict:
+        """Render this fieldset as a JSON schema fragment."""
         section = schema.generate_section(self.section)
         section["properties"].update(super().build_schema(schema, form_fields)["properties"])
         return {
@@ -69,4 +85,4 @@ class Fieldset(LayoutNode):
 
 
 class Layout(LayoutNode):
-    ...
+    """Full form layout as the root node."""