code: func CrossPlatformUbiquity(chain []*x509.Certificate) int {
  	// There is no root store info, every chain is equal weighted as 0.
  	if len(Platforms) == 0 {
  		return 0
  	}
  
  	totalWeight := 0
  	// A chain is viable with the platform if
  	//	1. the root is in the platform's root store
  	//	2. the chain satisfy the minimal constraints on hash function and key algorithm.
  	root := chain[len(chain)-1]
  	for _, platform := range Platforms {
  		if platform.Trust(root) {
  			switch {
  			case platform.HashUbiquity <= ChainHashUbiquity(chain) && platform.KeyAlgoUbiquity <= ChainKeyAlgoUbiquity(chain):
  				totalWeight += platform.Weight
  			}
  		}
  	}
  	return totalWeight
  }
docs: // CrossPlatformUbiquity returns a ubiquity score (presumably relecting the market share in percentage)
  // based on whether the given chain can be verified with the different platforms' root certificate stores.