input: Write a function to perform matrix addition.
  assert matrix_addition([[1, 2], [3, 4]], [[5, 6], [7, 8]]) == [[6, 8], [10, 12]]
  assert matrix_addition([[1, 0], [0, 1]], [[0, 1], [1, 0]]) == [[1, 1], [1, 1]]
  assert matrix_addition([[2, 3], [4, 5]], [[1, 0], [0, 1]]) == [[3, 3], [4, 6]]
output: def matrix_addition(matrix1, matrix2):
      rows = len(matrix1)
      cols = len(matrix1[0])
      result = [[0 for _ in range(cols)] for _ in range(rows)]
      
      for i in range(rows):
          for j in range(cols):
              result[i][j] = matrix1[i][j] + matrix2[i][j]
      
      return result