def image_from(from_value):
regex = re.compile(r"""<STR_LIT>""")<EOL>match = re.match(regex, from_value)<EOL>return match.group('<STR_LIT:image>', '<STR_LIT:name>') if match else (None, None)<EOL>
:param from_value: string like "image:tag" or "image:tag AS name"
:return: tuple of the image and stage name, e.g. ("image:tag", None)