def load_weights(self):
if self.network_weights_loader:<EOL><INDENT>self.network_weights = self.network_weights_loader()<EOL>self.network_weights_loader = None<EOL><DEDENT>
Load weights by evaluating self.network_weights_loader, if needed.

After calling this, self.network_weights_loader will be None and
self.network_weights will be the weights list, if available.