input: 
  def initialize_linear_regression_model(input_dim: int, output_dim: int) -> LinearRegressionModel:
      """ Initialize a linear regression model with given input and output dimensions.
      >>> model = initialize_linear_regression_model(3, 2)
      >>> model.weights.shape == (3, 2)
      True
      >>> model.bias.shape == (1, 2)
      True
      """
      return LinearRegressionModel(input_dim, output_dim)
  
output:     class LinearRegressionModel:
          def __init__(self, input_dim: int, output_dim: int):
              self.weights = np.random.randn(input_dim, output_dim)
              self.bias = np.random.randn(1, output_dim)