exceptions.py

from constants import DNA_ALPHABET, RNA_ALPHABET, RNA_CODON_TABLE


SIGNS = ('<', '>', '<=', '>=', '=')


class InvalidSignError(Exception):
    def __init__(self, sign, message=None):
        if message is None:
            message = f'Your sign = {sign} must be one of {SIGNS}!'
        super().__init__(message)


class IterableLengthError(Exception):
    def __init__(self, iterable, sign, value, message=None):
        if sign not in SIGNS:
            raise InvalidSignError(sign)
        if message is None:
            variable = [name for name, i in locals().items() if i == iterable][0]
            message = f'Error: len({variable}) = {len(iterable)} must be {sign} {value}!'
        super().__init__(message)


class StringIsNotDNAError(Exception):
    def __init__(self, message=None):
        if message is None:
            message = 'Error: Your string is not a valid DNA string!\n\
                It must be composed using ' + DNA_ALPHABET + ' alphabet!'
        super().__init__(message)


class StringIsNotRNAError(Exception):
    def __init__(self, message=None):
        if message is None:
            message = 'Error: Your string is not a valid RNA string!\n\
                It must be composed using ' + RNA_ALPHABET + ' alphabet!'
        super().__init__(message)


class StringIsNotProteinError(Exception):
    def __init__(self, message=None):
        if message is None:
            message = 'Error: Your string is not a valid protein string!\n\
                It must be composed using ' + set(RNA_CODON_TABLE.values()) + ' alphabet!'
        super().__init__(message)