docs(frozen_dataclass): convert code examples to executable doctests

Author: tony

src/libtmux/_internal/frozen_dataclass_sealable.py

@@ -84,23 +84,28 @@ def mutable_during_init(
 
     Examples
     --------
-    .. code-block:: python
-
-        @frozen_dataclass_sealable
-        class Example:
-            # Using field with metadata directly (recommended)
-            items: list[str] = field(
-                default_factory=list,
-                metadata={"mutable_during_init": True}
-            )
-
-            # Alternative approach using the decorator
-            @mutable_during_init
-            def values(self) -> dict[str, int]:
-                return {}
-
-            # Regular immutable field
-            name: str
+    >>> from dataclasses import field
+    >>> from libtmux._internal.frozen_dataclass_sealable import (
+    ...     frozen_dataclass_sealable, mutable_during_init
+    ... )
+    >>> 
+    >>> @frozen_dataclass_sealable
+    ... class Example:
+    ...     # Regular immutable field (required fields must come first)
+    ...     name: str
+    ...     # Using field with metadata directly (recommended approach)
+    ...     items: list[str] = field(
+    ...         default_factory=list,
+    ...         metadata={"mutable_during_init": True}
+    ...     )
+    >>> 
+    >>> # Create an instance
+    >>> example = Example(name="test-example")
+    >>> 
+    >>> # Can modify mutable field
+    >>> example.items.append("item1")
+    >>> example.items
+    ['item1']
     """
     if field_method is None:
         # Used with parentheses: @mutable_during_init()
@@ -209,38 +214,77 @@ def frozen_dataclass_sealable(
     --------
     Basic usage:
     
-    .. code-block:: python
-    
-        @frozen_dataclass_sealable
-        class Config:
-            name: str
-
-            values: dict[str, int] = field(
-                default_factory=dict,
-                metadata={"mutable_during_init": True}
-            )
+    >>> from dataclasses import field
+    >>> from typing import Optional
+    >>> from libtmux._internal.frozen_dataclass_sealable import (
+    ...     frozen_dataclass_sealable, is_sealable
+    ... )
+    >>> 
+    >>> @frozen_dataclass_sealable
+    ... class Config:
+    ...     name: str
+    ...     values: dict[str, int] = field(
+    ...         default_factory=dict,
+    ...         metadata={"mutable_during_init": True}
+    ...     )
+    >>> 
+    >>> # Create an instance
+    >>> config = Config(name="test-config")
+    >>> config.name
+    'test-config'
+    >>> 
+    >>> # Cannot modify frozen field
+    >>> try:
+    ...     config.name = "modified"
+    ... except AttributeError:
+    ...     print("Cannot modify frozen field")
+    Cannot modify frozen field
+    >>> 
+    >>> # Can modify mutable field
+    >>> config.values["key1"] = 100
+    >>> config.values
+    {'key1': 100}
+    >>> 
+    >>> # Seal the object
+    >>> config.seal()
+    >>> 
+    >>> # Can still modify the contents of mutable containers after sealing
+    >>> config.values["key2"] = 200
+    >>> config.values
+    {'key1': 100, 'key2': 200}
 
     With deferred sealing:
     
-    .. code-block:: python
-    
-        @frozen_dataclass_sealable
-        class Node:
-            value: int
-
-            next_node: Optional['Node'] = field(
-                default=None,
-                metadata={"mutable_during_init": True}
-            )
-
-        # Create a linked list
-        node1 = Node(value=1)  # Not sealed automatically
-        node2 = Node(value=2)  # Not sealed automatically
-        node1.next_node = node2
-
-        # Seal nodes
-        node1.seal()
-        node2.seal()
+    >>> @frozen_dataclass_sealable
+    ... class Node:
+    ...     value: int
+    ...     next_node: Optional['Node'] = field(
+    ...         default=None,
+    ...         metadata={"mutable_during_init": True}
+    ...     )
+    >>> 
+    >>> # Create a linked list
+    >>> node1 = Node(value=1)  # Not sealed automatically
+    >>> node2 = Node(value=2)  # Not sealed automatically
+    >>> node1.next_node = node2
+    >>> 
+    >>> # Verify structure
+    >>> node1.value
+    1
+    >>> node2.value
+    2
+    >>> node1.next_node is node2
+    True
+    >>> 
+    >>> # Seal nodes
+    >>> node1.seal()
+    >>> node2.seal()
+    >>> 
+    >>> # Verify sealed status
+    >>> hasattr(node1, "_sealed") and node1._sealed
+    True
+    >>> hasattr(node2, "_sealed") and node2._sealed
+    True
     """
     # Support both @frozen_dataclass_sealable and @frozen_dataclass_sealable() usage
     if cls is None: