input: Write a function to add two matrices and return the resulting matrix. If the dimensions of the two matrices are not the same, return 'Matrices not compatible'.
  
  def add_matrix(matrix1, matrix2):
      if len(matrix1) != len(matrix2) or len(matrix1[0]) != len(matrix2[0]):
          return 'Matrices not compatible'
      
      result = [[matrix1[i][j] + matrix2[i][j] for j in range(len(matrix1[0]))] for i in range(len(matrix1))]
      
      return result
  
  assert add_matrix([[1,2],[3,4]], [[1,2],[3,4]])==[[2,4],[6,8]]
  assert add_matrix([[1,2],[3,4]], [[0,1],[2,0]])==[[1,3],[5,4]]
  assert add_matrix([[1,2,3]], [[4,5,6]])==[[5,7,9]]
  assert add_matrix([[1],[2],[3]], [[4],[5],[6]])==[[5],[7],[9]]
  assert add_matrix([[1,2],[3,4]], [[1],[2]])=='Matrices not compatible'
  assert add_matrix([[1,2],[3,4]], [[1,2]])=='Matrices not compatible'
output: def add_matrix(matrix1, matrix2):
      if len(matrix1) != len(matrix2) or len(matrix1[0]) != len(matrix2[0]):
          return 'Matrices not compatible'
      
      result = [[matrix1[i][j] + matrix2[i][j] for j in range(len(matrix1[0]))] for i in range(len(matrix1))]
      
      return result