contains (string) {
    if (this.cs === false) {
      string = string.toLowerCase()
    }

    if (string.length === 0) {
      return this.$
    }

    // Otherwise, we need to continue searching
    const firstLetter = string[0]
    const next = this.dictionary[firstLetter]

    // If we don't have a node, this isn't a word
    if (!next) {
      return false
    }

    // Otherwise continue the search at the next node
    return next.contains(string.substring(1))
  }
A function to search the given string and return true if it lands
on on a word. Essentially testing if the word exists in the database.