code: def _check_colname(*columns):
      """
      Check if given column names conflict with `settings.from_columns` (ends with '_' or contains '__').
  
      :param columns: the column names to check
      :type columns: str
  
      :return: None
      :rtype: None
      :raise: ``ValueError`` if column names are invalid.
      """
  
      for col in columns:
          if str(col).endswith("_"):
              raise ValueError(
                  "Dict keys are not allowed to end with '_': {}".format(
                      col
                  )
              )
  
          if "__" in str(col):
              raise ValueError(
                  "Dict keys are not allowed to contain '__': {}".format(
                      col
                  )
              )
  
imports: import itertools
  from collections import defaultdict, namedtuple
  from typing import Iterable, Sized
  import pandas
label_desc: Use image node_id 2 for calling a global function with example usage: _check_colname() without return types