title: Objective-C: from nullable pointer 'NSURL * _Nullable' to non-nullable pointer type 'NSURL * _Nonnull'
body: <p>I'm trying to convert <code>NSURL * _Nullable</code> to non-nullable. By any chance any of you knows how can I do this?.</p>
  
  <p>Here is some context:</p>
  
  <p>I'm trying to use <a href="https://github.com/couchbaselabs/ios-oauthconsumer" rel="noreferrer">ios-oauthconsumer</a>, and I'm trying to initialize some objects:</p>
  
  <pre><code>self.requestTokenRequest = [[OAMutableURLRequest alloc] initWithURL:_requestTokenUrl
                                                                 consumer:_consumer
                                                                    token:nil
                                                                    realm:nil
                                                        signatureProvider:nil
                                                                    nonce:nil
                                                                timestamp:nil];
  </code></pre>
  
  <p>They are been initialize by this init:</p>
  
  <pre><code>- (id)initWithURL:(NSURL *)aUrl
           consumer:(OAConsumer *)aConsumer
              token:(OAToken *)aToken
              realm:(NSString *)aRealm
  signatureProvider:(id&lt;OASignatureProviding&gt;)aProvider
              nonce:(NSString *)aNonce
          timestamp:(NSString *)aTimestamp {
      if ((self = [self initWithURL:aUrl consumer:aConsumer token:aToken realm:aRealm signatureProvider:aProvider])) {
        nonce = [aNonce copy];
        timestamp = [aTimestamp copy];
      }
  
      return self;
  }
  </code></pre>
  
  <p>if I po I get this:</p>
  
  <p><a href="https://i.stack.imgur.com/KPF8x.png" rel="noreferrer"><img src="https://i.stack.imgur.com/KPF8x.png" alt="enter image description here"></a></p>
  
  <p>and I try to use that object. I get this warning:</p>
  
  <p><a href="https://i.stack.imgur.com/Xdt6c.png" rel="noreferrer"><img src="https://i.stack.imgur.com/Xdt6c.png" alt="enter image description here"></a>
  I'll really appreciate if any of you knows how to convert _Nullable to non-Nullable object.</p>