human
Solve the following python programming problem given the following code:
def _dereference(cmd, references) : 
    ' Dereference references in the template command, to refer
    to objects in the reference mapping

    Parameters
    ----------
    cmd : Command string
    references : mapping from template tags to objects

    Returns
    -------
    A new command, where all the tags have been subsituted as follows:
      "{tag}" -> \'data[references["tag"], __view]\', if references[tag] is a ComponentID
      "{tag}" -> \'references["tag"].to_mask(__view)\' if references[tag] is a Subset

    __view is a placeholder variable referencing the view
    passed to data.__getitem__ and subset.to_mask

    Raises
    ------
    TypeError, if a tag in the command maps to something other than
    a ComponentID or Subset object
    ' 
    def sub_func(match) : 
        tag = match.group ('tag') 
        if isinstance (references [tag], ComponentID) : 
            return ('data[references["%s"], __view]' % tag) 
else : 
            if isinstance (references [tag], Subset) : 
                return ('references["%s"].to_mask(__view)' % tag) 
else : 
                raise TypeError (('Tag %s maps to unrecognized type: %s' % (tag, type (references [tag])))) 
return TAG_RE.sub (references, cmd) 

    
    

    Fix the buggy line: return TAG_RE.sub (references, cmd)
assistant
#Here is Python program to fix the buggy line: return TAG_RE.

return TAG_RE.sub (def sub_func(, cmd)