Update ndcube/ndcube.py

Co-authored-by: DanRyanIrish <ryand5@tcd.ie>

ndcube/ndcube.py

@@ -975,10 +975,10 @@
         if isinstance(value, NDData) and value.wcs is None:
             if self.unit is not None and value.unit is not None:
                 value_data = (value.data * value.unit).to_value(self.unit)
-            elif self.unit is None:
+            elif self.unit is None and value.unit is None:
                 value_data = value.data
             else:
                 raise TypeError("Cannot add unitless NDData to a unitful NDCube.")
 
             # check whether there is a mask.
             # Neither self nor value has a mask
@@ -991,26 +991,26 @@
 
                 # combine the uncertainty;
                 if self.uncertainty is not None and value.uncertainty is not None:
                     new_uncertainty = self.uncertainty.propagate(
                         np.add, value, result_data = kwargs["data"], correlation=0
                     )
                     kwargs["uncertainty"] = new_uncertainty
                 elif self.uncertainty is not None:
                     new_uncertainty = self.uncertainty
                     kwargs["uncertainty"] = new_uncertainty
                 elif value.uncertainty is not None:
                     new_uncertainty = value.uncertainty
                 else:
                     new_uncertainty = None
             else:
                 # TODO
                 # When there is a mask, that is when the two new added parameters (OIM and HM) come into the picture.
                 # Conditional statements to permutate the two different scenarios (when it does not ignore the mask).
                 if operation_ignores_mask is False:
                     if handle_mask is np.logical_and:
                         pass
                     else:
                         pass
                 else:
                     raise NotImplementedError
 
@@ -1030,7 +1030,7 @@
         elif self.unit not in (None, u.Unit("")):
             raise TypeError("Cannot add a unitless object to an NDCube with a unit.")
         else:
             kwargs["data"] = self.data + value
 
         # return the new NDCube instance
         return self._new_instance(**kwargs)
@@ -1047,7 +1047,7 @@
         # tidying this up.
         if  (value_masked or (self_masked and hasattr(value,'uncertainty') and value.uncertainty is not None)): # value has a mask,
             # let the users call the add method
             raise TypeError('Please use the add method.')
 
         return self.add(value) # the mask keywords cannot be given by users.