Add try/except to import calinski_harabasz_score (PR #905)
Add try/except to import calinski_harabasz_score (PR #905)

This PR fixes #902 by wrapping our Elbow Visualizer's import of calinski_harabasz_score in a try/except to cover all versions of sklearn (which corrected the spelling from calinski_harabaz_score in 0.21.2).
DistrictDataLabs/yellowbrick