common_functions.py

import datetime
import re
from typing import List, Optional, TypeVar

ChoiceType = TypeVar("ChoiceType")


def select_from_list(choices: List[ChoiceType], choice_name: str, none_is_option: bool = False) -> ChoiceType:
    query_user = True
    return_value: ChoiceType = None
    while query_user:
        print(f'Choose the {choice_name} from this list:')
        number_of_choices = len(choices)
        for i in range(number_of_choices):
            print(f'{i + 1})\t{choices[i]}'.expandtabs(4))
        if none_is_option:
            print('0)\tNone of the above'.expandtabs(4))
        selection = input('Enter selection: ')
        try:
            selection_value = int(selection)
            if none_is_option and selection_value == 0:
                return_value = None
                query_user = False
            elif selection_value < 1 or selection_value > number_of_choices:
                raise ValueError('Selection out of range.')
            else:
                return_value = choices[selection_value - 1]
                query_user = False
        except ValueError:
            print(f'\tSelection must be an integer between {0 if none_is_option else 1} '
                  f'and {number_of_choices}, inclusive!')
    return return_value


def strip_html(text: Optional[str]) -> Optional[str]:
    if text is not None:
        return re.sub(re.compile('<.*?>'), '', text)
    else:
        return None


def semester_stamp() -> str:
    today = datetime.date.today()
    year: int = today.year
    month: int = today.month
    # Normalize month to semester start
    if month < 5:
        month = 1
    elif month < 8:
        month = 5
    else:
        month = 8
    return f'{year}-0{month}'