diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 41a7cd6..f6ebb19 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -6,7 +6,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: [ '3.6', '3.7', '3.8', '3.9', '3.10' ]
+        python-version: [ '3.11', '3.12', '3.13' ]
 
     steps:
       - uses: actions/checkout@v2
diff --git a/README.md b/README.md
index 40a4ba9..cf59f85 100644
--- a/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ To install:
 
 `pip install mock-firestore`
 
-Python 3.6+ is required for it to work.
+Python 3.7+ is required for it to work.
 
 ## Usage
 
@@ -105,7 +105,7 @@ transaction.commit()
 ```
 
 ## Running the tests
-* Create and activate a virtualenv with a Python version of at least 3.6
+* Create and activate a virtualenv with a Python version of at least 3.7
 * Install dependencies with `pip install -r requirements-dev-minimal.txt`
 * Run tests with `python -m unittest discover tests -t /`
 
diff --git a/mockfirestore/document.py b/mockfirestore/document.py
index 24aa433..6e64926 100644
--- a/mockfirestore/document.py
+++ b/mockfirestore/document.py
@@ -1,7 +1,7 @@
 from copy import deepcopy
 from functools import reduce
 import operator
-from typing import List, Dict, Any
+from typing import List, Dict, Any, Union
 from mockfirestore import NotFound
 from mockfirestore._helpers import (
     Timestamp, Document, Store, get_by_path, set_by_path, delete_by_path
@@ -22,8 +22,8 @@ def id(self):
     def exists(self) -> bool:
         return self._doc != {}
 
-    def to_dict(self) -> Document:
-        return self._doc
+    def to_dict(self) -> Union[Dict[str, Any], None]:
+        return self._doc if self.exists else None
 
     @property
     def create_time(self) -> Timestamp:
@@ -39,7 +39,7 @@ def read_time(self) -> Timestamp:
         timestamp = Timestamp.from_now()
         return timestamp
 
-    def get(self, field_path: str) -> Any:
+    def get(self, field_path: str, timeout: float = None) -> Any:
         if not self.exists:
             return None
         else:
@@ -63,13 +63,13 @@ def __init__(self, data: Store, path: List[str],
     def id(self):
         return self._path[-1]
 
-    def get(self) -> DocumentSnapshot:
+    def get(self, timeout: float=None) -> DocumentSnapshot:
         return DocumentSnapshot(self, get_by_path(self._data, self._path))
 
-    def delete(self):
+    def delete(self, timeout: float=None):
         delete_by_path(self._data, self._path)
 
-    def set(self, data: Dict, merge=False):
+    def set(self, data: Dict, merge=False, timeout: float=None):
         if merge:
             try:
                 self.update(deepcopy(data))
@@ -78,7 +78,7 @@ def set(self, data: Dict, merge=False):
         else:
             set_by_path(self._data, self._path, deepcopy(data))
 
-    def update(self, data: Dict[str, Any]):
+    def update(self, data: Dict[str, Any], timeout: float=None):
         document = get_by_path(self._data, self._path)
         if document == {}:
             raise NotFound('No document to update: {}'.format(self._path))
diff --git a/setup.py b/setup.py
index f55cb88..0fa1489 100644
--- a/setup.py
+++ b/setup.py
@@ -14,11 +14,12 @@
     packages=setuptools.find_packages(),
     test_suite='',
     classifiers=[
-        'Programming Language :: Python :: 3.6',
         'Programming Language :: Python :: 3.7',
         'Programming Language :: Python :: 3.8',
         'Programming Language :: Python :: 3.9',
         'Programming Language :: Python :: 3.10',
+        'Programming Language :: Python :: 3.11',
+        'Programming Language :: Python :: 3.12',
         "License :: OSI Approved :: MIT License",
     ],
-)
\ No newline at end of file
+)