code: def _drop_unnamed_null_columns(df: pl.DataFrame) -> pl.DataFrame:
      """If DataFrame contains unnamed columns that contain only nulls, drop them."""
      null_cols = []
      for col_name in df.columns:
          # note that if multiple unnamed columns are found then all but
          # the first one will be ones will be named as "_duplicated_{n}"
          if col_name == "" or re.match(r"_duplicated_\d+$", col_name):
              if df[col_name].null_count() == len(df):
                  null_cols.append(col_name)
      if null_cols:
          df = df.drop(*null_cols)
      return df
  
imports: from __future__ import annotations
  import re
  from io import StringIO
  from pathlib import Path
  from typing import TYPE_CHECKING, Any, BinaryIO, Callable, NoReturn, Sequence, overload
  import polars._reexport
  from polars import functions
  from polars.datatypes import Date, Datetime
  from polars.exceptions import NoDataError, ParameterCollisionError
  from polars.io.csv.functions import read_csv
  from polars.utils.various import normalize_filepath
label_desc: Use image node_id 19 for calling a global function with example usage: _drop_unnamed_null_columns(df) and returns: df