code: def check_git_version():
      
      try:
          version = git_version()
      except exceptions.SimplGitCommandError:
          warnings.warn("Git does not appear to be installed!",
                        exceptions.GitWarning)
          return
  
      ver_num = version.split()[2]
      major, minor, _ = ver_num.split('.', 2)
      major = int(major)
      minor = int(minor)
      if (major, minor) < MIN_GIT_VERSION:
          warnings.warn(
              "Git version %(ver)s found. %(rec)s or greater "
              "is recommended for simpl/git.py"
              % dict(ver=ver_num,
                     rec='.'.join((str(x) for x in MIN_GIT_VERSION))),
              exceptions.GitWarning)
docs: Check the installed git version against a known-stable version.
  
      If the git version is less then ``MIN_GIT_VERSION``, a warning is raised.
  
      If git is not installed at all on this system, we also raise a warning for
      that.
  
      The original reason why this check was introduced is because with older
      versions git (< 1.9), newly init-ed git repos cannot checkout from a
      fetched remote unless the repo has at least one commit in it. The reason
      for this is that before creating a commit, the HEAD refers to a
      refs/heads/master file which doesn't exist yet.
  
      .. todo::
  
          TODO(larsbutler): If we wanted to be defensive about this and favor
          compatibility over elegance, we could just automatically add a
          `git commit` (empty, no message) after every `git init`. I would
          recommend doing this in the :class:`GitRepo` class, not in the
          module-level util functions. Adding an extra commit shouldn't cause
          any problems.