Add usage example to MDHistoToWorkspace2D-v1.rst re #9726

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>

Code/Mantid/docs/source/algorithms/MDHistoToWorkspace2D-v1.rst

@@ -19,4 +19,30 @@ This tool is useful as many algorithms in Mantid only apply to
 Workspace2D. After conversion with MDHistoToWorkspace2D such algorithms
 can also be applied to MD data.
 
+Usage
+-----
+
+**Example - Flatten a small workspace:**
+
+.. testcode:: ExMDHistoToWorkspace2D
+
+   # Create input workspace
+   CreateMDWorkspace(Dimensions=3, Extents='-10,10,-10,10,-10,10', Names='A,B,C', Units='U,U,U', OutputWorkspace='demo')
+   FakeMDEventData(InputWorkspace='demo', PeakParams='32,0,0,0,1')
+   input = BinMD(InputWorkspace='demo', AlignedDim0='A,-2,2,4', AlignedDim1='B,-2,2,4', AlignedDim2='C,-2,2,4')
+
+   # Run the algorithm 
+   output = MDHistoToWorkspace2D(InputWorkspace='input')
+
+   # print 6th group of 4 bins in both input and output workspaces
+   print "part of MD workspace",input.getSignalArray()[1,1]
+   print "corresponding part of 2D workspace",output.dataY(5) 
+
+Output:
+
+.. testoutput:: ExMDHistoToWorkspace2D
+
+   part of MD workspace [ 0.  4.  5.  0.]
+   corresponding part of 2D workspace [ 0.  4.  5.  0.]
+
 .. categories::