validate_initial

pyrcs.utils.validate_initial(initial, as_is=False)[source]

Validates if a value is a single ASCII letter.

Parameters:

  • initial (str) – The input value to validate, which is expected to be a string representing a single letter.

  • as_is (bool) – If as_is=True, the function returns the letter in its original case; if as_is=False (default), the letter is returned in uppercase.

Returns:

The validated initial letter.

Return type:

str

Raises:

  • ValueError – If the input is not a single ASCII letter.

  • TypeError – If the input is not a string.

Examples:

>>> from pyrcs.utils import validate_initial
>>> validate_initial('x')
'X'
>>> validate_initial('x', as_is=True)
'x'
>>> validate_initial('xyz')
Traceback (most recent call last):
  ...
    ...
ValueError: 'xyz' is invalid; it must be a single letter (A-Z, a-z).