code: def check_basename_conflicts(self, targets):
      
  
      basename_seen = {}
      for target in targets:
        if target.basename in basename_seen:
          raise self.BasenameConflictError('Basename must be unique, found two targets use '
                                           "the same basename: {}'\n\t{} and \n\t{}"
                                           .format(target.basename,
                                                   basename_seen[target.basename].address.spec,
                                                   target.address.spec))
        basename_seen[target.basename] = target
docs: Apps' basenames are used as bundle directory names. Ensure they are all unique.