code: def convert_df_dtype_to_str(df):
      return df.astype(str)
  
file_path: autogluon/tabular/src/autogluon/tabular/models/tabular_nn/utils/data_preprocessor.py
imports: from collections import OrderedDict
  from sklearn.compose import ColumnTransformer
  from sklearn.impute import SimpleImputer
  from sklearn.pipeline import Pipeline
  from sklearn.preprocessing import FunctionTransformer, QuantileTransformer, StandardScaler
  from .categorical_encoders import OneHotMergeRaresHandleUnknownEncoder, OrdinalMergeRaresHandleUnknownEncoder
label_desc: Use image node_id 2 for calling a global function with example usage: convert_df_dtype_to_str(df) and returns: df