Fix 'param_bool' missing

Author: SteveLTN

iex/batch.py

@@ -12,7 +12,8 @@
 import datetime
 import json
 from pandas import Series
-from iex.utils import (parse_date,
+from iex.utils import (param_bool,
+ parse_date,
  validate_date_format,
  validate_range_set,
  validate_output_format,