old_contents: """HDL Code generation."""
  
  from scoff.codegen import CodeGenerator
  from .stmt import HDLStatement
  
  
  class HDLCodeGenerator(CodeGenerator):
      """HDL Code generator."""
  
      def _check_validity(self, element):
          if isinstance(element, HDLStatement):
              if element.is_legal() is False:
                  return False
  
          return True
  
new_contents: """HDL Code generation."""
  
  from scoff.codegen import CodeGenerator
  from .stmt import HDLStatement
  
  
  class HDLCodeGenerator(CodeGenerator):
      """HDL Code generator."""
  
      def _check_validity(self, element):
          if isinstance(element, HDLStatement):
              if element.is_legal() is False:
                  return False
  
          return True
  
      # basic types to be implemented
      def gen_HDLIntegerConstant(self, element, **kwargs):
          """Generate Integer constants."""
          raise NotImplementedError
  
      def gen_HDLStringConstant(self, element, **kwargs):
          """Generate String constants."""
          raise NotImplementedError
  
      def gen_HDLVectorDescriptor(self, element, **kwargs):
          """Generate Vector elements."""
          raise NotImplementedError
  
      def gen_HDLModulePort(self, element, **kwargs):
          """Generate ports."""
          raise NotImplementedError
  
subject: make consistent with old implementation