class_docstr: Transformer that returns the sum all series as one series.
code: def _predict_core(self, df: pd.DataFrame) -> pd.Series:
      return df.sum(axis=1, skipna=False)
  
imports: from typing import Any, Callable, Dict, Optional, Tuple, Union
  import pandas
  from sklearn.decomposition import PCA
  from .._transformer_base import _NonTrainableMultivariateTransformer, _TrainableMultivariateTransformer
label_desc: Use image node_id 3 for calling the SumAll obj's underlying member method code with example usage: obj._predict_core(df) and returns: df