# File lib/grape/middleware/versioner/accept_version_header.rb, line 20
        def before
          potential_version = (env[Grape::Http::Headers::HTTP_ACCEPT_VERSION] || '').strip

          if strict?
            # If no Accept-Version header:
            if potential_version.empty?
              throw :error, status: 406, headers: error_headers, message: 'Accept-Version header must be set.'
            end
          end

          return if potential_version.empty?

          # If the requested version is not supported:
          throw :error, status: 406, headers: error_headers, message: 'The requested version is not supported.' unless versions.any? { |v| v.to_s == potential_version }

          env[Grape::Env::API_VERSION] = potential_version
        end