input: Write a python function to train a logistic regression model on the first two features of the iris dataset and return the trained model.
  assert isinstance(train_logistic_regression(), LogisticRegression)
output: def train_logistic_regression():
      from sklearn.datasets import load_iris
      from sklearn.linear_model import LogisticRegression
      
      # Load the iris dataset
      iris = load_iris()
      X = iris.data[:, :2]  # Use only the first two features
      y = iris.target
      
      # Train the Logistic Regression model
      model = LogisticRegression()
      model.fit(X, y)
      
      return model