def nest(label, nested)
      indented = indent
      indented.puts("#{label}:")
      nested.pretty_dump(indented.indent)
      self
    end
def nest(label, nested)
      indented = indent
      indented.puts("#{label}:")
      nested.pretty_dump(indented.indent)
      self
    end
Write nest with label

 @param [String] label
 @param [#pretty_dump] nested

 @return [self]

 @api private