Extract shared named style constant and use keyword args

- Extract VALID_NAMED_STYLE_TYPES constant in docs_helpers.py, reuse in validation_manager.py
- Switch build_paragraph_style call to keyword arguments for clarity and resilience

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

gdocs/docs_helpers.py

@@ -10,6 +10,18 @@ from typing import Dict, Any, Optional
 
 logger = logging.getLogger(__name__)
 
+VALID_NAMED_STYLE_TYPES = (
+    "NORMAL_TEXT",
+    "TITLE",
+    "SUBTITLE",
+    "HEADING_1",
+    "HEADING_2",
+    "HEADING_3",
+    "HEADING_4",
+    "HEADING_5",
+    "HEADING_6",
+)
+
 
 def _normalize_color(
     color: Optional[str], param_name: str
@@ -137,15 +149,10 @@ def build_paragraph_style(
     fields = []
 
     if named_style_type is not None:
-        valid_styles = [
-            "NORMAL_TEXT", "TITLE", "SUBTITLE",
-            "HEADING_1", "HEADING_2", "HEADING_3",
-            "HEADING_4", "HEADING_5", "HEADING_6",
-        ]
-        if named_style_type not in valid_styles:
+        if named_style_type not in VALID_NAMED_STYLE_TYPES:
             raise ValueError(
                 f"Invalid named_style_type '{named_style_type}'. "
-                f"Must be one of: {', '.join(valid_styles)}"
+                f"Must be one of: {', '.join(VALID_NAMED_STYLE_TYPES)}"
             )
         paragraph_style["namedStyleType"] = named_style_type
         fields.append("namedStyleType")
@@ -360,15 +367,15 @@ def create_update_paragraph_style_request(
         Dictionary representing the updateParagraphStyle request, or None if no styles provided
     """
     paragraph_style, fields = build_paragraph_style(
-        heading_level,
-        alignment,
-        line_spacing,
-        indent_first_line,
-        indent_start,
-        indent_end,
-        space_above,
-        space_below,
-        named_style_type,
+        heading_level=heading_level,
+        alignment=alignment,
+        line_spacing=line_spacing,
+        indent_first_line=indent_first_line,
+        indent_start=indent_start,
+        indent_end=indent_end,
+        space_above=space_above,
+        space_below=space_below,
+        named_style_type=named_style_type,
     )
 
     if not paragraph_style:

gdocs/managers/validation_manager.py

@@ -9,7 +9,7 @@ import logging
 from typing import Dict, Any, List, Tuple, Optional
 from urllib.parse import urlparse
 
-from gdocs.docs_helpers import validate_operation
+from gdocs.docs_helpers import validate_operation, VALID_NAMED_STYLE_TYPES
 
 logger = logging.getLogger(__name__)
 
@@ -317,15 +317,10 @@ class ValidationManager:
             )
 
         if named_style_type is not None:
-            valid_styles = [
-                "NORMAL_TEXT", "TITLE", "SUBTITLE",
-                "HEADING_1", "HEADING_2", "HEADING_3",
-                "HEADING_4", "HEADING_5", "HEADING_6",
-            ]
-            if named_style_type not in valid_styles:
+            if named_style_type not in VALID_NAMED_STYLE_TYPES:
                 return (
                     False,
-                    f"Invalid named_style_type '{named_style_type}'. Must be one of: {', '.join(valid_styles)}",
+                    f"Invalid named_style_type '{named_style_type}'. Must be one of: {', '.join(VALID_NAMED_STYLE_TYPES)}",
                 )
 
         if heading_level is not None: