code: def vcs_command(self, fnames, action):
          
          try:
              for path in sorted(fnames):
                  vcs.run_vcs_tool(path, action)
          except vcs.ActionToolNotFound as error:
              msg = _("For %s support, please install one of the<br/> "
                      "following tools:<br/><br/>  %s")\
                          % (error.vcsname, ', '.join(error.tools))
              QMessageBox.critical(self, _("Error"),
                  _("""<b>Unable to find external program.</b><br><br>%s""")
                      % to_text_string(msg))
docs: VCS action (commit, browse)