```ruby
module Cucumber
  module Ast
    # Represents an inline argument in a step. Example:
    #
    #   Given the message
    #     """
    #     I like
    #     Cucumber sandwich
    #     """
    #
    # The text between the pair of <tt>"""</tt> is stored inside a PyString,
    # which is yielded to the StepDefinition block as the last argument.
    #
    # The StepDefinition can then access the String via the #to_s method. In the
    # example above, that would return: <tt>"I like\nCucumber sandwich"</tt>
    #
    # Note how the indentation from the source is stripped away.
    #
    class PyString
      def initialize(string)
        @string = string
      end

      def to_s
        @string.split("\n", -1).map{|line| line.lstrip}.join("\n")
      end

      def accept(visitor, status)
        visitor.visit_py_string(to_s, status)
      end
      
      # For testing only
      def to_sexp #:nodoc:
        [to_s]
      end
                
    end
  end
end
```

Add symbol for sexp pystring representation
user
```ruby
module Cucumber
  module Ast
    # Represents an inline argument in a step. Example:
    #
    #   Given the message
    #     """
    #     I like
    #     Cucumber sandwich
    #     """
    #
    # The text between the pair of <tt>"""</tt> is stored inside a PyString,
    # which is yielded to the StepDefinition block as the last argument.
    #
    # The StepDefinition can then access the String via the #to_s method. In the
    # example above, that would return: <tt>"I like\nCucumber sandwich"</tt>
    #
    # Note how the indentation from the source is stripped away.
    #
    class PyString
      def initialize(string)
        @string = string
      end

      def to_s
        @string.split("\n", -1).map{|line| line.lstrip}.join("\n")
      end

      def accept(visitor, status)
        visitor.visit_py_string(to_s, status)
      end
      
      # For testing only
      def to_sexp #:nodoc:
        [:pystring, to_s]
      end
                
    end
  end
end
```
assistant