import numpy as np

lista  = [[4,5,3,15,4],
          [20,17,3,4,56],
          [5,6,2,90,32],
          [18,7,1,8,13],
          [0,20,30,4,7]]

arr = np.asarray(lista)
np.place(arr, arr<=4, [10])

print(arr)