add dummy extractor

bob/learn/pytorch/extractor/audio/DummyExtractor.py

+import numpy
+from bob.bio.base.extractor import Extractor
+
+class DummyExtractor(Extractor):
+  """ The Dummy class for passing the extracted embedding.
+
+  """
+  def __init__(self):
+    """ Init function
+    """
+    super(DummyExtractor, self).__init__()
+  
+  def __call__(self, data):
+    """__call__(data) -> feature
+
+    This function will actually perform the feature extraction.
+    It must be overwritten by derived classes.
+    It takes the (preprocessed) data and returns the features extracted from the data.
+
+    **Parameters**
+
+    data : object (usually :py:class:`numpy.ndarray`)
+      The *preprocessed* data from which features should be extracted.
+
+    **Returns:**
+
+    feature : object (usually :py:class:`numpy.ndarray`)
+      The extracted feature.
+    """
+    return data
\ No newline at end of file