code: def __run_pre_all(self):
          
  
          # if the list of delta dirs is [delta1, delta2] the pre scripts of delta2 are
          # executed before the pre scripts of delta1
  
          for d in reversed(self.dirs):
              pre_all_py_path = os.path.join(d, 'pre-all.py')
              if os.path.isfile(pre_all_py_path):
                  print('     Applying pre-all.py...', end=' ')
                  self.__run_py_file(pre_all_py_path, 'pre-all')
                  print('OK')
  
              pre_all_sql_path = os.path.join(d, 'pre-all.sql')
              if os.path.isfile(pre_all_sql_path):
                  print('     Applying pre-all.sql...', end=' ')
                  self.__run_sql_file(pre_all_sql_path)
                  print('OK')
docs: Execute the pre-all.py and pre-all.sql files if they exist