The wrong lake.?

In the ballet “Swan Lake” (with music by Tchaikovsky) there were two swans,
one black and one white – the action is the battle between love and evil.
In the play, both roles are danced by the same ballerina.
According to connoisseurs, the most difficult role in the world of ballet.

Either this french lake isn’t that kind of swan lake,
or hopefully so love has won over evil.?
Because it is clear that both swans are white.