code: def _read_credential_file(self, cfg):
          
          self.username = cfg.get("rackspace_cloud", "username")
          try:
              self.password = cfg.get("rackspace_cloud", "api_key", raw=True)
          except ConfigParser.NoOptionError as e:
              # Allow either the use of either 'api_key' or 'password'.
              self.password = cfg.get("rackspace_cloud", "password", raw=True)
docs: Parses the credential file with Rackspace-specific labels.