add comment to explain operation

theano/tensor/var.py

@@ -501,6 +501,8 @@ class _tensor_py_operators(object):
             args[ellipsis_at: ellipsis_at + 1] = (
                 [slice(None)] * (self.ndim - (len(args) - 1 - new_axes)))
 
+        # Force input to be int64 datatype if input is an empty list or tuple
+        # Else leave it as is if it is a real number
         args = tuple([numpy.array(inp, dtype=numpy.int64)
                       if(inp == [] or inp == ()) else inp for inp in args])
         # Convert python literals to theano constants