code: def set_target_variable (self, targets, variable, value, append=0):
          
          if isinstance (targets, str):
              targets = [targets]
          if isinstance(value, str):
              value = [value]
  
          assert is_iterable(targets)
          assert isinstance(variable, basestring)
          assert is_iterable(value)
  
          if targets:
              if append:
                  bjam_interface.call("set-target-variable", targets, variable, value, "true")
              else:
                  bjam_interface.call("set-target-variable", targets, variable, value)
docs: Sets a target variable.
  
          The 'variable' will be available to bjam when it decides
          where to generate targets, and will also be available to
          updating rule for that 'taret'.