class RBS::Writer

def preserve_empty_line(prev, decl)
  # @type var decl: _Located
  return unless prev
  if (_ = decl).respond_to?(:comment)
    if comment = (_ = decl).comment
      decl = comment
    end
  end
  prev_loc = prev.location
  decl_loc = decl.location
  if prev_loc && decl_loc
    prev_end_line = prev_loc.end_line
    start_line = decl_loc.start_line
    if start_line - prev_end_line > 1
      puts
    end
  else
    # When the signature is not constructed by the parser,
    # it always inserts an empty line.
    puts
  end
end