code: def source_decode(sourcecode, verbose=0):
      
      tmp_path = sourcecode.split('.')
      op_str = tmp_path.pop()
      import_str = '.'.join(tmp_path)
      try:
          if sourcecode.startswith('tpot.'):
              exec('from {} import {}'.format(import_str[4:], op_str))
          else:
              exec('from {} import {}'.format(import_str, op_str))
          op_obj = eval(op_str)
      except Exception as e:
          if verbose > 2:
              raise ImportError('Error: could not import {}.\n{}'.format(sourcecode, e))
          else:
              print('Warning: {} is not available and will not be used by TPOT.'.format(sourcecode))
          op_obj = None
  
      return import_str, op_str, op_obj
docs: Decode operator source and import operator class.
  
      Parameters
      ----------
      sourcecode: string
          a string of operator source (e.g 'sklearn.feature_selection.RFE')
      verbose: int, optional (default: 0)
          How much information TPOT communicates while it's running.
          0 = none, 1 = minimal, 2 = high, 3 = all.
          if verbose > 2 then ImportError will rasie during initialization
  
  
      Returns
      -------
      import_str: string
          a string of operator class source (e.g. 'sklearn.feature_selection')
      op_str: string
          a string of operator class (e.g. 'RFE')
      op_obj: object
          operator class (e.g. RFE)