Please explain the python code step by step . And knapsack is P or NP ? And give an input ,output and list content after calling the function. Thanks in advance!

def knapsack(w,v,c):

items = []

while len(v)>0 :

value = max(v)

index = v.index(value)

if c-w[index]>=0:

items +=[[w[index],value]]

c -= w[index]

v.pop(index)

w.pop(index)

return items