      "Derben": "Derbe",
      "Derberen": "Derbere",
      "Derbsten": "Derbste",
      "Derbys": "Derby",
      "Dereinstige": "dereinstig",
      "Dereinstigen": "Dereinstige",
      "Derer": "der",
      "Derjenige": "derjenige",
      "Derjenigen": "derjenige",
 
</s>
    "Der": "der",
      "Derben": "Derbe",
      "Derberen": "Derbere",
      "Derbsten": "Derbste",
      "Derbys": "Derby",
    "Der": "der",
      "Dereinstige": "dereinstig",
      "Dereinstigen": "Dereinstige",
      "Derer": "der",
      "Derjenige": "derjenige",
      "Derjenigen": "derjenige",
keep keep keep add keep keep keep keep keep
 German lemmatizer additions (#2529)

* lemma of was-> was

* added new pairs issue @2486

* added article tests
spacy/lang/de/lemmatizer.py