<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def check_wide_data_for_blank_choices(choice_col, wide_data):
 """ Checks `wide_data` for null values in the choice column, and raises a helpful ValueError if null values are found. Parameters choice_col : str. Denotes the column in `wide_data` that is used to record each observation's choice. wide_data : pandas dataframe. Contains one row for each observation. Should contain `choice_col`. Returns ------- None. """

    if wide_data[choice_col].isnull().any():
        msg_1 = "One or more of the values in wide_data[choice_col] is null."
        msg_2 = " Remove null values in the choice column or fill them in."
        raise ValueError(msg_1 + msg_2)

    return None