Contributing to django.

I have got this error in section //Writing your first patch for Django//

when i performed this below  command in terminal.
i have got an error.

git clone git@github.com:YourGitHubName/django.git


error part :

Cloning into 'django'...
Warning: Permanently added the RSA host key for IP address '192.30.253.113' to the list of known hosts.
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

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