def check_csv(csv_name):
    """ Checks if a CSV has three columns: response_date, user_id, nps_rating

    Args:
        csv_name (str): The name of the CSV file.

    Returns:
        Boolean: True if the CSV is valid, False otherwise 
    """
    # Open csv_name as f using with open
    with open(csv_name, 'r') as f:
        first_line = f.readline()
        # Return true if the CSV has the three specified columns
        if first_line == "response_date,user_id,nps_rating\n":
            return True
        # Otherwise, return false    
        else:
            return False