Write timestamps to file as dataset attributes along with data

bob/io/stream/stream.py

@@ -862,7 +862,16 @@ class StreamSave(StreamFilter):
             raise ValueError("Output file is not a valid StreamFile.")
 
     def put(self, data, timestamp=None):
-        self.file.put_frame(self.name, data)
+        """Pass data and timestamp to the :obj:`~bob.io.stream.StreamFile` to write to disk.
+
+        Parameters
+        ----------
+        data : :obj:`numpy.ndarray`
+            data to write to file.
+        timestamp : int or float
+            Timestamp of `data`, by default None.
+        """
+        self.file.put_frame(self.name, data, timestamp)
 
 
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