title: How do I delete a similar alembic version?
body: <p>When I am trying to do </p>
  
  <pre><code>alembic upgrade head
  </code></pre>
  
  <p>I am getting this error:</p>
  
  <pre><code>ERROR [alembic.util.messaging] Online migration expected to match one row when updating '3aae6532b560' to 'a1d8dae7cc' in 'alembic_version'; 2 found
  FAILED: Online migration expected to match one row when updating '3aae6532b560'
  to 'a1d8dae7cc' in 'alembic_version'; 2 found
  </code></pre>
  
  <p><code>alembic current</code></p>
  
  <p>gives two similar versions of alembic like:</p>
  
  <pre><code>3aae6532b560
  3aae6532b560
  </code></pre>
  
  <p>How do I delete one of the similar versions of alembic, i.e a copied version?</p>
  
  <p>alembic history doesn't show any messed up output.</p>
  
  <p>Thanks!</p>