code: func Similarity(str1, str2 string, p *Params) float64 {
  	return Match(str1, str2, p.Clone().BonusThreshold(1.1)) // guaranteed no bonus
  }
docs: // Similarity returns a score in the range of 0..1 for how similar the two strings are.
  // A score of 1 means the strings are identical, and 0 means they have nothing in common.
  //
  // A nil third argument uses the default cost of 1 for all three operations.
  //
  // If a non-zero MinScore value is provided in the parameters, scores lower than it
  // will be returned as 0.