def _shallow_clone(self, ref, git_cmd):  
git_config = '<STR_LIT>'<EOL>git_cmd('<STR_LIT:-c>', git_config, '<STR_LIT>', '<STR_LIT>', ref, '<STR_LIT>')<EOL>git_cmd('<STR_LIT>', ref)<EOL>git_cmd(<EOL>'<STR_LIT:-c>', git_config, '<STR_LIT>', '<STR_LIT>', '<STR_LIT>',<EOL>'<STR_LIT>', '<STR_LIT>',<EOL>)<EOL>
Perform a shallow clone of a repository and its submodules