diff --git a/simplemind/__init__.py b/simplemind/__init__.py
index b98e75c..2c7ca0e 100644
--- a/simplemind/__init__.py
+++ b/simplemind/__init__.py
@@ -32,3 +32,13 @@ def generate_text(prompt, *, llm_model=None, llm_provider=None):
     provider = find_provider(llm_provider)
 
     return provider.generate_text(prompt=prompt, llm_model=llm_model)
+
+
+__all__ = [
+    "Conversation",
+    "SimpleMind",
+    "create_conversation",
+    "find_provider",
+    "generate_data",
+    "generate_text",
+]
diff --git a/simplemind/models.py b/simplemind/models.py
index f53c35d..5846489 100644
--- a/simplemind/models.py
+++ b/simplemind/models.py
@@ -4,8 +4,7 @@ from typing import Any, Dict, List, Literal, Optional
 
 from pydantic import BaseModel, Field
 
-from .utils import find_provider
-
+from simplemind.utils import find_provider
 
 MESSAGE_ROLE = Literal["system", "user", "assistant"]
 
@@ -53,8 +52,12 @@ class Conversation(SMBaseModel):
     def __str__(self):
         return f"<Conversation id={self.id!r}>"
 
-    def add_message(self, role: MESSAGE_ROLE, text: str, meta: Dict[str, Any] = {}):
+    def add_message(
+        self, role: MESSAGE_ROLE, text: str, meta: Optional[Dict[str, Any]] = None
+    ):
         """Add a new message to the conversation."""
+        if meta is None:
+            meta = {}
         self.messages.append(Message(role=role, text=text, meta=meta))
 
     def send(
diff --git a/simplemind/providers/__init__.py b/simplemind/providers/__init__.py
index 5941019..9e38db1 100644
--- a/simplemind/providers/__init__.py
+++ b/simplemind/providers/__init__.py
@@ -1,8 +1,9 @@
 from typing import List, Type
-from .anthropic import Anthropic
-from .groq import Groq
-from .openai import OpenAI
-from .xai import XAI
-from ._base import BaseProvider
+
+from simplemind.providers._base import BaseProvider
+from simplemind.providers.anthropic import Anthropic
+from simplemind.providers.groq import Groq
+from simplemind.providers.openai import OpenAI
+from simplemind.providers.xai import XAI
 
 providers: List[Type[BaseProvider]] = [Anthropic, Groq, OpenAI, XAI]
diff --git a/simplemind/settings.py b/simplemind/settings.py
index ae81a64..54ed61f 100644
--- a/simplemind/settings.py
+++ b/simplemind/settings.py
@@ -1,4 +1,5 @@
 from typing import Optional, Union
+
 from pydantic import Field, SecretStr, field_validator
 from pydantic_settings import BaseSettings, SettingsConfigDict
 
diff --git a/simplemind/utils.py b/simplemind/utils.py
index c1bd2b7..38e0c0d 100644
--- a/simplemind/utils.py
+++ b/simplemind/utils.py
@@ -1,5 +1,6 @@
 from typing import Union
-from .providers import providers
+
+from simplemind.providers import providers
 
 
 def find_provider(provider_name: Union[str, None]):