text: from __future__ import annotations
  
  from numpy.typing import ArrayLike
  from sklearn.linear_model import LinearRegression
  
  from .regression_model import RegressionModel
  
  
  class LinearModel(RegressionModel):
      def __init__(self):
          self._lin_regressor: LinearRegression | None = None
  
      def learn(self, x_train: ArrayLike, y_train: ArrayLike):
          lin_regressor = LinearRegression()
          lin_regressor.fit(x_train, y_train)
          self._lin_regressor = lin_regressor
  
      def predict(self, x_test: ArrayLike) -> ArrayLike:
          lin_regressor = self._lin_regressor
          return lin_regressor.predict(x_test)
  