numpy.polysub() in Python

numpy.polysub() :This function helps to find the difference of two polynomials and then returning the result as a polynomial. Each input polynomial must be a sequence of polynomial coefficients, from highest to lowest degree.

Parameters : 
p1 : Input polynomial 1 :  1x + 2.
p2 : Input polynomial 2 :  9x2 + 5x + 4

Return:

Difference of polynomials :  (0-9)x2 + (1-5)x + (2-4)

Python3 1==

# Python code explaining 
# numpy.polysub ()

# importing libraries
import numpy as np

p1 = np.poly1d([1, 2])
p2 = np.poly1d([9, 5, 4])

print ("P1 : ", p1)
print ("\nP2 : \n", p2)

a = np.polysub(p1, p2)

print ("\nP1 - P2 : \n", a)

Output:

P1 :   
1 x + 2

P2 : 
    2
9 x + 5 x + 4

P1 - P2 : 
     2
-9 x - 4 x - 2