diff --git a/gpt_engineer/applications/cli/cli_agent.py b/gpt_engineer/applications/cli/cli_agent.py
index a3247cdd0c..3422d0cf5d 100644
--- a/gpt_engineer/applications/cli/cli_agent.py
+++ b/gpt_engineer/applications/cli/cli_agent.py
@@ -113,7 +113,8 @@ def init(self, prompt: str) -> FilesDict:
         entrypoint = gen_entrypoint(
             self.ai, files_dict, self.memory, self.preprompts_holder
         )
-        files_dict = FilesDict(files_dict | entrypoint)
+        combined_dict = {**files_dict, **entrypoint}
+        files_dict = FilesDict(combined_dict)
         files_dict = self.process_code_fn(
             self.ai,
             self.execution_env,
@@ -135,7 +136,8 @@ def improve(
             entrypoint = gen_entrypoint(
                 self.ai, files_dict, self.memory, self.preprompts_holder
             )
-            files_dict = FilesDict(files_dict | entrypoint)
+            combined_dict = {**files_dict, **entrypoint}
+            files_dict = FilesDict(combined_dict)
         files_dict = self.process_code_fn(
             self.ai,
             self.execution_env,
diff --git a/gpt_engineer/benchmark/run.py b/gpt_engineer/benchmark/run.py
index af2e4bffa6..277b95d945 100644
--- a/gpt_engineer/benchmark/run.py
+++ b/gpt_engineer/benchmark/run.py
@@ -1,13 +1,18 @@
 import time
 
+from typing import List, Optional
+
 from gpt_engineer.benchmark.types import Assertable, Benchmark, TaskResult
 from gpt_engineer.core.base_agent import BaseAgent
 from gpt_engineer.core.default.disk_execution_env import DiskExecutionEnv
 
 
 def run(
-    agent: BaseAgent, benchmark: Benchmark, task_name: str | None = None, verbose=False
-) -> list[TaskResult]:
+    agent: BaseAgent,
+    benchmark: Benchmark,
+    task_name: Optional[str] = None,
+    verbose=False,
+) -> List[TaskResult]:
     task_results = []
     for task in benchmark.tasks:
         t0 = time.time()
diff --git a/gpt_engineer/benchmark/types.py b/gpt_engineer/benchmark/types.py
index fd70fa7b8c..d8357c9320 100644
--- a/gpt_engineer/benchmark/types.py
+++ b/gpt_engineer/benchmark/types.py
@@ -1,6 +1,6 @@
 from dataclasses import dataclass
 from subprocess import Popen
-from typing import Callable
+from typing import Callable, Dict, Optional
 
 from gpt_engineer.core.base_execution_env import BaseExecutionEnv
 from gpt_engineer.core.files_dict import FilesDict
@@ -21,9 +21,9 @@ class Assertable:
 
     files: FilesDict
     env: BaseExecutionEnv
-    process: Popen | None
-    stdout: str | None
-    stderr: str | None
+    process: Optional[Popen]
+    stdout: Optional[str]
+    stderr: Optional[str]
 
 
 Assertion = Callable[[Assertable], bool]
@@ -32,10 +32,10 @@ class Assertable:
 @dataclass
 class Task:
     name: str
-    initial_code: FilesDict | None
-    command: str | None
+    initial_code: Optional[FilesDict]
+    command: Optional[str]
     prompt: str
-    assertions: dict[str, Assertion] | None
+    assertions: Optional[Dict[str, Assertion]]
 
 
 @dataclass
@@ -44,7 +44,7 @@ class Benchmark:
 
     name: str
     tasks: list[Task]
-    timeout: int | None = None
+    timeout: Optional[int] = None
 
 
 @dataclass
diff --git a/gpt_engineer/core/default/simple_agent.py b/gpt_engineer/core/default/simple_agent.py
index 795b46864f..0965511514 100644
--- a/gpt_engineer/core/default/simple_agent.py
+++ b/gpt_engineer/core/default/simple_agent.py
@@ -56,7 +56,8 @@ def init(self, prompt: str) -> FilesDict:
         entrypoint = gen_entrypoint(
             self.ai, files_dict, self.memory, self.preprompts_holder
         )
-        files_dict = FilesDict(files_dict | entrypoint)
+        combined_dict = {**files_dict, **entrypoint}
+        files_dict = FilesDict(combined_dict)
         return files_dict
 
     def improve(