# File lib/librarian/resolver/implementation.rb, line 36
      def initialize(resolver, spec, options = { })
        unrecognized_options = options.keys - [:cyclic]
        unrecognized_options.empty? or raise Error,
          "unrecognized options: #{unrecognized_options.join(", ")}"
        self.resolver = resolver
        self.spec = spec
        self.cyclic = !!options[:cyclic]
        @level = 0
      end