code: def test_two_gram_fingerprint(self):
      assert fn.twoGramFingerprint("don4ld") == {"4ldoldn4on"}
      assert fn.twoGramFingerprint("donald 1992") == {
          "199299ald1doldnaon"
      }
      assert fn.twoGramFingerprint("g00fy  ") == {"000ffyg0"}
      assert fn.twoGramFingerprint(" c1p   c10p ") == {"0p101pc1pc"}
      assert fn.twoGramFingerprint("7") == frozenset()
  
      def prevImpl(field: str):
          if len(field) > 1:
              return frozenset(
                  (
                      "".join(
                          sorted(
                              gram.strip()
                              for gram in set(
                                  ngrams(field.replace(" ", ""), 2)
                              )
                          )
                      ),
                  )
              )
          else:
              return frozenset()
  
      assert fn.twoGramFingerprint("don4ld") == prevImpl("don4ld")
      assert fn.twoGramFingerprint("donald 1992") == prevImpl(
          "donald 1992"
      )
      assert fn.twoGramFingerprint("g00fy") == prevImpl("g00fy")
      assert fn.twoGramFingerprint(" c1p   c10p "), prevImpl(
          " c1p   c10p "
      )
      assert fn.twoGramFingerprint("a") == prevImpl("a")
  
imports: import unittest
  from dedupe import predicate_functions
  from dedupe.cpredicates import ngrams
label_desc: Use image node_id 15 for calling the TestPredicateFunctions obj's underlying member method code with example usage: obj.test_two_gram_fingerprint() and returns: frozenset, frozenset