class SyntaxTree::HshPtn

def format_contents(q, parts, nested)
  keyword_rest = self.keyword_rest
  q.group { q.seplist(parts) { |part| q.format(part, stackable: false) } }
  # If there isn't a constant, and there's a blank keyword_rest, then we
  # have an plain ** that needs to have a `then` after it in order to
  # parse correctly on the next parse.
  if !constant && keyword_rest && keyword_rest.value.nil? && !nested
    q.text(" then")
  end
end