title: Gitpython - can't clone from remote repo using private ssh key
body: <p>I'm trying to clone a project from git using Python's Gitpython library, but instead of password i want to use ssh keys for authentication. I've created a pair of private and public keys and put the public in git and the private in the project directory. In my code i'm using the following commands:</p>
  
  <p>My import:</p>
  
  <pre><code>from git import Repo
  </code></pre>
  
  <p>The clone command:</p>
  
  <pre><code>ssh_cmd = 'ssh -i private_key.ppk'
  Repo.clone_from(GIT_USERS_URL, local_git_dir, env={'GIT_SSH_COMMAND': ssh_cmd})
  </code></pre>
  
  <p>'private_key.ppk' is the name of the private key file.</p>
  
  <p>When running the script i get the following error:</p>
  
  <pre><code>Permission denied, please try again.
  Permission denied, please try again.
  Permission denied (publickey,gssapi-keyex,gssapi-with-mic,password).
  fatal: Could not read from remote repository.
  Please make sure you have the correct access rights
  and the repository exists.
  </code></pre>
  
  <p>I know this question has been asked a lot but none of the solutions worked and i don't see why ? </p>
  
  <p>I also run the following commands before i reach the clone statement:</p>
  
  <pre><code>git_process = git.Git(**path to folder to be pushed later on to git**)
  git_process.update_environment(SSH_KEY=SSH_PRIVATE_KEY)
  </code></pre>
  
  <p>Where SSH_PRIVATE_KEY is the path to the private key.</p>
  
  <p>What am i missing ?</p>
  
  <p>Thanks !</p>