input: from typing import List
  
  def linear_regression_nn(input_dim: int, output_dim: int) -> 'LinearRegressionModel':
      """ Creates an instance of the LinearRegressionModel class for a neural network with specified input and output dimensions.
      >>> model = linear_regression_nn(3, 1)
      >>> model.forward(np.array([[1, 2, 3]]))
      array([[0.]])
      """
      return LinearRegressionModel(input_dim, output_dim)
output:     class LinearRegressionModel:
          def __init__(self, input_dim: int, output_dim: int):
              self.weights = np.zeros((input_dim, output_dim))
              self.bias = np.zeros(output_dim)
  
          def forward(self, x: np.ndarray) -> np.ndarray:
              return np.dot(x, self.weights) + self.bias