Warning while saving object of class

Hello all: I have been given a script 'scriptName.m' that includes the following four lines of code:

hws = get_param(bdroot, 'modelworkspace');

hws.DataSource = 'MAT-File';

hws.FileName = 'filename_xyz';

hws.saveToSource;

On execution of the script, I get the following warning, repeated several times:

Warning: While saving an object of class 'matlabshared.scopes.UnifiedScope':

Method 'saveobj' is not defined for class 'matlabshared.scopes.UnifiedScope'

or is removed from MATLAB's search path.

> In scriptName (line 145)

Line 145 is the last line "hws.saveToSource;" of the four lines quoted above.

I cannot find any information in the help or online on what this warning means or what causes it, and thus on how I may avoid it. Does anyone know of any documentation relating to this warning message? The term 'scopes' suggests that it is related to a Simulink model, which is plausible, but is that true? Thanks in advance.