Fails to find function

FirebaseAuth/Sources/Swift/AuthProvider/GitHubAuthProvider.swift

@@ -27,12 +27,12 @@ import Foundation
      @param token The GitHub OAuth access token.
      @return An AuthCredential containing the GitHub credentials.
   */
-  @objc public class func credential(withToken token:String) -> AuthCredential {
+  @objc public class func credential(withToken token:String) -> GitHubAuthCredential {
     return GitHubAuthCredential(withToken: token)
   }
 }
 
-@objc(FIRGitHubAuthCredential) fileprivate class GitHubAuthCredential: AuthCredential, NSSecureCoding {
+@objc(FIRGitHubAuthCredential) open class GitHubAuthCredential: AuthCredential, NSSecureCoding {
   private let token: String
 
   init(withToken token:String) {
@@ -40,17 +40,17 @@ import Foundation
     super.init(provider: GitHubAuthProvider.id)
   }
 
-  func prepareVerifyAssertionRequest(request: FIRVerifyAssertionRequest) {
+  public func prepareVerifyAssertionRequest2(request: FIRVerifyAssertionRequest) {
     request.providerAccessToken = token
   }
 
-  static var supportsSecureCoding = true
+  public static var supportsSecureCoding = true
 
-  func encode(with coder: NSCoder) {
+  public func encode(with coder: NSCoder) {
     coder.encode(token)
   }
 
-  required init?(coder: NSCoder) {
+  public required init?(coder: NSCoder) {
     guard let token = coder.decodeObject(forKey: "token") as? String else {
       return nil
     }

FirebaseAuth/Tests/Unit/FIRGitHubAuthProviderTests.m

@@ -48,11 +48,11 @@ static NSString *const kFirebaseAppID = @"appID";
 - (void)testCredentialWithToken {
   FIRAuthRequestConfiguration *requestConfiguration =
       [[FIRAuthRequestConfiguration alloc] initWithAPIKey:kAPIKey appID:kFirebaseAppID];
-  FIRAuthCredential *credential = [FIRGitHubAuthProvider credentialWithToken:kGitHubToken];
+  FIRGitHubAuthCredential *credential = [FIRGitHubAuthProvider credentialWithToken:kGitHubToken];
   FIRVerifyAssertionRequest *request =
       [[FIRVerifyAssertionRequest alloc] initWithProviderID:FIRGitHubAuthProvider.id
                                        requestConfiguration:requestConfiguration];
-  [credential prepareVerifyAssertionRequest:request];
+  [credential prepareVerifyAssertionRequest2:request];
   XCTAssertEqualObjects(request.providerAccessToken, kGitHubToken);
 }