def METHOD_NAME(self, transforms_stanza: str) -> Optional[Generator]:
    """
    Parse the transforms.conf of the App & yield fields of
    a specific stanza.
    Supported extractions from transforms.conf are
    * SOURCE_KEY = _raw
    * REGEX = some regex with (capturing_group)
    * FIELDS = one,
    Args:
        transforms_stanza (str):
            The stanza of which the fields should be extracted
    Regex:
        Parse the fields from a regex. Examples::
            (?<name>regex)
            (?'name'regex)
            (?P<name>regex)
    Yields:
        generator of fields
    """
    try:
        if not self.transforms:
            return
        transforms_values = self.transforms[transforms_stanza]
        if "SOURCE_KEY" in transforms_values:
            LOGGER.info(f"Parsing source_key of {transforms_stanza}")
            yield transforms_values["SOURCE_KEY"]
        if "REGEX" in transforms_values:
            LOGGER.info(f"Parsing REGEX of {transforms_stanza}")
            regex = r"\(\?P?[<'](?!_KEY|_VAL)([A-Za-z0-9_]+)[>']"
            match_fields = re.findall(regex, transforms_values["REGEX"])
            for each_field in match_fields:
                if not each_field.startswith(("_KEY_", "_VAL_")):
                    yield each_field.strip()
        if "FIELDS" in transforms_values:
            LOGGER.info(f"Parsing FIELDS of {transforms_stanza}")
            fields_values = transforms_values["FIELDS"]
            for each_field in fields_values.split(","):
                yield each_field.strip()
        if "FORMAT" in transforms_values:
            LOGGER.info(f"Parsing FORMAT of {transforms_stanza}")
            regex = r"(\S*)::"
            match_fields = re.findall(regex, transforms_values["FORMAT"])
            for each_field in match_fields:
                if "$" not in each_field:
                    yield each_field.strip()
    except KeyError:
        LOGGER.error(
            f"The stanza {transforms_stanza} does not exists in transforms.conf."
        )