[core][dataset] Add method for obtaining metadata info for a key

darfix/core/dataset.py

@@ -404,6 +404,10 @@ class Dataset():
             _logger.info("Dimension {} of size {} has been added for reshaping"
                          .format(dimension.name, dimension.size))
 
+    def get_metadata_values(self, kind, key):
+        return numpy.unique([data.get_value(kind=kind, name=key)[0] for data
+                             in self.data.metadata])
+
     def __compute_changing_value(self, values, changing_value=1):
         """
         Recursive method used to calculate how fast is a dimension. The speed of a dimension is the number of