method
    
    dump
  dump()
  public
  Produces a version of str with all non-printing characters replaced by nnn notation and all special characters escaped.
"hello \n ''".dump #=> "\"hello \\n ''\"
  dump()
  public
  Produces a version of str with all non-printing characters replaced by nnn notation and all special characters escaped.
"hello \n ''".dump #=> "\"hello \\n ''\"