code: def _flatten_series(series: np.ndarray) -> np.ndarray:
      if len(series.shape) > 2:
          raise Exception(
              f"Input data should be shaped (A,) or (A, 1), got {series.shape}"
          )
      elif len(series.shape) == 2:
          series = series.flatten()
      return series
  
file_path: lightwood/lightwood/helpers/ts.py
imports: from typing import Tuple, Dict
  from datetime import datetime
  import numpy
  import pandas
label_desc: Use image node_id 6 for calling the Differencer obj's underlying member method code with example usage: obj._flatten_series(series) and returns: series