Blocks of Python code, and indeed entire scripts, can be embedded in Csound orchestras using the {{ and }} directives to enclose the script, as follows:

sr=44100
kr=4410
ksmps=10
nchnls=1
pyinit

giSinusoid	ftgen	0,	0, 8192, 10,	1

pyruni {{
import random

pool = [(1 + i/10.0) ** 1.2 for i in range(100)]

def get_number_from_pool(n, p):
    if random.random() < p:
        i = int(random.random() * len(pool))
        pool[i] = n
    return random.choice(pool)
}}

instr 1
	k1	oscil	1, 3, giSinusoid	
	k2	pycall1	"get_number_from_pool", k1 + 2, p4
		printk	0.01, k2
endin