introduce SModelSUnit for type hinting

Author: WolfgangWaltenberger

smodels/base/physicsUnits.py

@@ -9,6 +9,7 @@
 """
 
 import unum
+SModelSUnit = unum.Unum # for type hinting
 
 # description see
 # http://home.scarlet.be/be052320/Unum.html
@@ -54,7 +55,11 @@
     Called as script, will print some base.physicsUnits.
 
     """
+    def getXSec() -> SModelSUnit:
+        return 3.0*fb
+
     three = 3.0 * fb
     print(three, "=", three.asUnit(pb))
     seven = 7.0 * TeV
     print(seven, "=", seven.asUnit(GeV))
+    print ( getXSec() )