public Builder expectedNumCommunities(final int expectedNumCommunities) {
            this.expectedNumCommunities = expectedNumCommunities;
            return this;
        }
Generates a synthetic network for provided vertices in the given graph such that the provided expected number
of communities are generated with the specified expected number of edges.

@return The actual number of edges generated. May be different from the expected number.
gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/algorithm/generator/CommunityGenerator.java