code: def Assign(target, source):
      
      if not isinstance(target, list):
          target = [target]
      if not isinstance(source, list):
          source.prefix = u" "
          source = [source]
  
      return Node(syms.atom,
                  target + [Leaf(token.EQUAL, u"=", prefix=u" ")] + source)
docs: Build an assignment statement