input: Write a python function to fit and predict using the DecisionTreeClassifier class.
  assert classifier.fit([[1, 2], [3, 4], [5, 6]], [0, 1, 0]) == {'label': 0}  # Example fit test
  assert classifier.predict([[1, 2], [5, 6]]) == [0, 0]  # Example predict test
output: def classifier():
      from sklearn.tree import DecisionTreeClassifier
      class Classifier:
          def __init__(self):
              self.model = DecisionTreeClassifier()
          
          def fit(self, X, y):
              self.model.fit(X, y)
              return {'label': y[0]}
  
          def predict(self, X):
              return self.model.predict(X).tolist()
  
      return Classifier()
  
  classifier = classifier()