add docstring

app.py

@@ -3,9 +3,31 @@ from elevenlabs.client import ElevenLabs
 import tempfile
 import os
 
-def generate_speech(text, api_key, voice_id, model_id, language_code, output_format):
+def generate_speech(text = "", api_key = "", voice_id = "JBFqnCBsd6RMkjVDRZzb", model_id = "eleven_v3", language_code = "en", output_format = "mp3_22050_32"):
     """
     Convert input text to speech using ElevenLabs API and return the audio file path.
+
+    Args:
+    text (str): Required. The input text to be converted into speech.
+    api_key (str): Required. The ElevenLabs API key used to authenticate the request. This should be kept secret and treated like a password.
+
+    voice_id (str): The ID of the voice to use for speech generation. Default: "JBFqnCBsd6RMkjVDRZzb". Other available voices can be found at: https://elevenlabs.io/app/default-voices
+
+    model_id (str): The ID of the ElevenLabs model to use. Typically one of: "eleven_v3" (default) or "eleven_multilingual_v2"
+
+    language_code (str): The two-letter ISO 639-1 language code specifying the language of the input text. Example: "en" for English, "lv" for Latvian. Full list: https://en.wikipedia.org/wiki/List_of_ISO_639_language_codes
+
+    output_format (str): The desired output audio format. Default: "mp3_22050_32". Other formats are listed here: https://elevenlabs.io/docs/api-reference/text-to-speech/convert#request.query.output_format.output_format   
+
+    Returns:
+    tuple
+        A tuple containing:
+    
+        audio_file_path : str or None
+            The file path to the generated audio file if the speech synthesis was successful, or None if an error occurred.
+        
+        status_message : str
+            A human-readable message indicating the result of the operation, such as a success confirmation or an error description.
     """
     if not text.strip():
         return None, "❌ Text is empty."