Update plr.py

Author: PragyanTiwari

doubleml/plm/plr.py

@@ -108,7 +108,6 @@ def __init__(self,
         valid_scores = ['IV-type', 'partialling out']
         _check_score(self.score, valid_scores, allow_callable=True)
         is_reg = ml_l._estimator_type == "regressor"
-                     
         _ = self._check_learner(ml_l, 'ml_l', regressor=is_reg, classifier=not is_reg)
         ml_m_is_classifier = self._check_learner(ml_m, 'ml_m', regressor=True, classifier=True)
         self._learner = {'ml_l': ml_l, 'ml_m': ml_m}