class_docstr: Converts features in PandasDataFrame to VW format
  Ref: https://github.com/VowpalWabbit/vowpal_wabbit/wiki/Input-format
code: def __categorical_namespace_generator(
      self, feature, feature_name
  ) -> str:
      if pd.isnull(feature):
          return ""
      else:
          feature = str(feature).replace(" ", "_")
          return feature_name + "=" + self.__sanify(feature)
  
file_path: autogluon/tabular/src/autogluon/tabular/models/vowpalwabbit/vowpalwabbit_utils.py
imports: import pandas
  from autogluon.common.features.types import R_CATEGORY, R_FLOAT, R_INT, S_TEXT
label_desc: Use image node_id 6 for calling the VWFeaturesConverter obj's underlying member method code with example usage: obj.__categorical_namespace_generator(feature, feature_name) and returns: str, unknown