code: def retarget(self, remove=[], add=[]):
          
  
          archs = self.arch_list().split('/')
  
          for r in remove:
              if r in archs:
                  archs.remove(r)
  
          archs.extend(add)
  
          archstr = "/".join(archs)
          return self.family.find(archstr, self.module_name())
docs: Return a TargetSettings object for the same module but with some of the architectures
          removed and others added.