public Builder crossCommunityPercentage(final double percentage) {
            if (percentage < 0.0 || percentage > 1.0)
                throw new IllegalArgumentException("Percentage must be between 0 and 1");
            this.crossCommunityPercentage = percentage;
            return this;
        }
Sets the percentage of edges that cross a community, i.e. connect a vertex to a vertex in
another community. The lower this value, the higher the modularity of the generated communities.

@param percentage Percentage of community crossing edges. Must be in [0,1]
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/algorithm/generator/CommunityGenerator.java