def get_content_charset(self, failobj=None):
        missing = object()
        charset = self.get_param('charset', missing)
        if charset is missing:
            return failobj
        if isinstance(charset, tuple):
            # RFC 2231 encoded, so decode it, and it better end up as ascii.
            pcharset = charset[0] or 'us-ascii'
            try:
                # LookupError will be raised if the charset isn't known to
                # Python.  UnicodeError will be raised if the encoded text
                # contains a character not in the charset.
                charset = unicode(charset[2], pcharset).encode('us-ascii')
            except (LookupError, UnicodeError):
                charset = charset[2]
        # charset character must be in us-ascii range
        try:
            if isinstance(charset, str):
                charset = unicode(charset, 'us-ascii')
            charset = charset.encode('us-ascii')
        except UnicodeError:
            return failobj
        # RFC 2046, $4.1.2 says charsets are not case sensitive
        return charset.lower()
Establish that calling `delete` on a record that does not exist
dataset/ETHPy150Open babble/babble/include/jython/Lib/email/message.py/Message.get_content_charset--crossover with--dataset/ETHPy150Open ansible/tower-cli/tests/test_models_base.py/ResourceTests.test_delete_with_pk_already_missing