input: 
  from typing import List
  
  class Matrix:
      """Represents a matrix and provides a method to extract all the numbers from it
      as a list of integers. The matrix is a list of strings where each string is a row
      and the numbers are separated by spaces.
      Example:
      matrix = Matrix(["1 2 3", "4 5 6", "7 8 9"])
      print(matrix.extract_numbers()) == [1, 2, 3, 4, 5, 6, 7, 8, 9]
      """
      def __init__(self, matrix: List[str]):
          self.matrix = matrix
  
      def extract_numbers(self) -> List[int]:
          numbers = []
          for row in self.matrix:
              numbers.extend(map(int, row.split()))
          return numbers
  
output:     
      def extract_numbers(self) -> List[int]:
          numbers = []
          for row in self.matrix:
              numbers.extend(map(int, row.split()))
          return numbers
  