user: Give a detailed overview of AddonPreferences(bpy_struct): syntax, arguments, return values, common patterns.

assistant: # AddonPreferences(bpy_struct)

```
bl_info = {
    "name": "Example Add-on Preferences",
    "author": "Your Name Here",
    "version": (1, 0),
    "blender": (2, 65, 0),
    "location": "SpaceBar Search -> Add-on Preferences Example",
    "description": "Example Add-on",
    "warning": "",
    "doc_url": "",
    "tracker_url": "",
    "category": "Object",
}

import bpy
from bpy.types import Operator, AddonPreferences
from bpy.props import StringProperty, IntProperty, BoolProperty

class ExampleAddonPreferences(AddonPreferences):
    # This must match the add-on name, use `__package__`
    # when defining this for add-on extensions or a sub-module of a Python package.
    bl_idname = __name__

    filepath: StringProperty(
        name="Example File Path",
        subtype='FILE_PATH',
    )
    number: IntProperty(
        name="Example Number",
        default=4,
    )
    boolean: BoolProperty(
        name="Example Boolean",
        default=False,
    )

    def draw(self, context):
        layout = self.layout
        layout.label(text="This is a preferences view for our add-on")
        layout.prop(self, "filepath")
        layout.prop(self, "number")
        layout.prop(self, "boolean")

class OBJECT_OT_addon_prefs_example(Operator):
    """Display example preferences"""
    bl_idname = "object.addon_prefs_example"
    bl_label = "Add-on Preferences Example"
    bl_options = {'REGISTER', 'UNDO'}

    def execute(self, context):
        preferences = context.preferences
        addon_prefs = preferences.addons[__name__].preferences

        info = "Path: {:s}, Number: {:d}, Boolean {!r}".format(
            addon_prefs.filepath, addon_prefs.number, addon_prefs.boolean,
        )
        self.report({'INFO'}, info)
        print(info)

        return {'FINISHED'}

# Registration
def register():
    bpy.utils.register_class(OBJECT_OT_addon_prefs_example)
    bpy.utils.register_class(ExampleAddonPreferences)

def unregister():
    bpy.utils.unregister_class(OBJECT_OT_addon_prefs_example)
    bpy.utils.unregister_class(ExampleAddonPreferences)
```

base class — [`bpy_struct`](bpy.types.bpy_struct.html#bpy.types.bpy_struct "bpy.types.bpy_struct")

*class* bpy.types.AddonPreferences(*bpy_struct*)
:   bl_idname
    :   Type:
        :   string, default “”, (never None)

    bl_system_properties_get(*\**, *do_create=False*)
    :   DEBUG ONLY. Internal access to runtime-defined RNA data storage, intended solely for testing and debugging purposes. Do not access it in regular scripting work, and in particular, do not assume that it contains writable data

        Parameters:
        :   **do_create** (*boolean**,* *(**optional**)*) – Ensure that system properties are created if they do not exist yet

        Returns:
        :   The system properties root container, or None if there are no system properties stored in this data yet, and its creation was not requested

        Return type:
        :   [`PropertyGroup`](bpy.types.PropertyGroup.html#bpy.types.PropertyGroup "bpy.types.PropertyGroup")

    *classmethod* bl_rna_get_subclass(*id*, *default=None*, */*)
    :   Parameters:
        :   **id** (*str*) – The RNA type identifier.

        Returns:
        :   The RNA type or default when not found.

        Return type:
        :   [`bpy.types.Struct`](bpy.types.Struct.html#bpy.types.Struct "bpy.types.Struct") subclass

    *classmethod* bl_rna_get_subclass_py(*id*, *default=None*, */*)
    :   Parameters:
        :   **id** (*str*) – The RNA type identifier.

        Returns:
        :   The class or default when not found.

        Return type:
        :   type