code: def _validate_usecols_names(usecols, names):
      
      missing = [c for c in usecols if c not in names]
      if len(missing) > 0:
          raise ValueError(
              "Usecols do not match columns, "
              "columns expected but not found: {missing}".format(missing=missing)
          )
  
      return usecols
docs: Validates that all usecols are present in a given
      list of names. If not, raise a ValueError that
      shows what usecols are missing.
  
      Parameters
      ----------
      usecols : iterable of usecols
          The columns to validate are present in names.
      names : iterable of names
          The column names to check against.
  
      Returns
      -------
      usecols : iterable of usecols
          The `usecols` parameter if the validation succeeds.
  
      Raises
      ------
      ValueError : Columns were missing. Error message will list them.