title: how to solve the error of linker command failed with exit code 1 (use -v to see invocation)
body: <p>I got one error when I run my app. The error is <code>linker command failed with exit code 1 (use -v to see invocation)</code>.</p>
  
  <p>The error shows me that there are 2 duplicate symbols for architecture x86_64.</p>
  
  <p>I could not find a solution. How can I fix this?</p>
  
  <p><a href="https://i.stack.imgur.com/J3EMI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/J3EMI.png" alt="i also put that screenshot of error in xcode"></a></p>
  
  <p>Please help me for this issue.</p>