Docstring for capture_array()

Co-authored-by: Julian Stirling <julian@julianstirling.co.uk>

Author: JohemianKnapsody

src/labthings_picamera2/thing.py

@@ -537,7 +537,8 @@ def capture_array(
         It's likely to be highly inefficient - raw and/or uncompressed captures using
         binary image formats will be added in due course.
 
-        wait: float to pass to picamera as a timeout, raising an error if it is exceeded (seconds)
+        stream_name: (Optional) The PiCamera2 stream to use, should be one of ["main", "lores", "raw"]. Default = "main"
+        wait: (Optional, float) Set a timeout in seconds. A TimeoutError is raised if this time is exceeded during capture. Default = None
         """
         with self.picamera() as cam:
             return cam.capture_array(stream_name, wait = wait)