input: Write a python function that takes as input a 2D list `matrix` of dimensions m by n. This function should verify whether each cell `matrix[i][j]` satisfies two conditions: it is equal to the cell directly below it (`matrix[i+1][j]`, if it exists), and it is different from the cell immediately to its right (`matrix[i][j+1]`, if it exists). The function should return true if all cells in the matrix fulfill these requirements; otherwise, it should return false.
  
  Examples:
  >>> matrix = [[1,0,2],[1,0,2]]
  True
  >>> matrix = [[1,1,1],[0,0,0]]
  False
  >>> matrix = [[1],[2],[3]]
  False
  
  Constraints:
  - 1 <= m, n <= 10
  - 0 <= matrix[i][j] <= 9
output: 
  def verify_matrix(matrix):
      m = len(matrix)
      n = len(matrix[0])
      for i in range(m):
          for j in range(n):
              if i + 1 < m and matrix[i][j] != matrix[i + 1][j]:
                  return False
              if j + 1 < n and matrix[i][j] == matrix[i][j + 1]:
                  return False
      return True
  