    # File lib/json/pure/generator.rb, line 222
            def configure(opts)
              @indent         = opts[:indent] if opts.key?(:indent)
              @space          = opts[:space] if opts.key?(:space)
              @space_before   = opts[:space_before] if opts.key?(:space_before)
              @object_nl      = opts[:object_nl] if opts.key?(:object_nl)
              @array_nl       = opts[:array_nl] if opts.key?(:array_nl)
              @allow_nan      = !!opts[:allow_nan] if opts.key?(:allow_nan)
              @ascii_only     = opts[:ascii_only] if opts.key?(:ascii_only)
              @depth          = opts[:depth] || 0
              @quirks_mode    = opts[:quirks_mode] if opts.key?(:quirks_mode)
              if !opts.key?(:max_nesting) # defaults to 19
                @max_nesting = 19
              elsif opts[:max_nesting]
                @max_nesting = opts[:max_nesting]
              else
                @max_nesting = 0
              end
              self
            end