human
Complete the below
def GetServiceVersions(namespace):

    ''''Get all the versions for the service with specified namespace (partially) ordered
    by compatibility (i.e. any version in the list that is compatible with some version
    v in the list will preceed v)'
    '''
 Can you provide a the Python code you requested?
assistant
#Here is the Python code you requested.
    def compare(a, b):
        if (a == b):
            return 0
        if (b in parentMap[a]):
            return (-1)
        if (a in parentMap[b]):
            return 1
        return ((a > b) - (a < b))
    if PY3:
        return sorted([v for (v, n) in iteritems(serviceNsMap) if (n == namespace)], key=cmp_to_key(compare))
    else:
        return sorted([v for (v, n) in iteritems(serviceNsMap) if (n == namespace)], compare)