code: function validVersion(version, spec) {
    // Normalize route versions
    var test = spec.versions || [spec.version]
  
    // Check for direct version match
    if (~test.indexOf(version)) {
      return true
    }
  
    // Use semver and attempt to match on supplied version
    return !!test.filter(function(v) {
      return semver.satisfies(v, version)
    }).length
  }
docs: Check if a version is valid for a given route spec
  
  @param {String} version
  @param {Object} route specification
  @return {Boolean} valid
  @api private