'Detect if the supplied application configuration is a Flocker
compatible format.
A Flocker configuration is a dictionary containing, at a minimum,
a version key containing an integer version number  and an applications
key containing a mapping of application names to definitions.'

def is_valid_format(self):

    valid = False
    flocker_keys = set([u'version', u'applications'])
    present_keys = set(self._application_configuration)
    if flocker_keys.issubset(present_keys):
        valid = True
        for application in self._application_configuration[u'applications'].values():
            if (not isinstance(application, dict)):
                valid = False
            elif (u'image' not in application):
                valid = False
    return valid
