code: def remove_auxiliary_variable(self):
          
  
          if not self.has_auxiliary_variable():
  
              # do nothing, but print a warning
  
              warnings.warn("Cannot remove a non-existing auxiliary variable", RuntimeWarning)
  
          else:
  
              # Remove the law from the children
  
              self._remove_child(self._aux_variable['law'].name)
  
              # Clean up the dictionary
  
              self._aux_variable = {}
  
              # Set the parameter to the status it has before the auxiliary variable was created
  
              self.free = self._old_free
docs: Remove an existing auxiliary variable
  
          :return: