Prime factor finder

pffinder.py

# This program takes an integer and returns it prime factors

# isprime checks whether an integer greater than 2 is prime
def isprime(candn):
    half = candn / 2
    divisor = 2
    while divisor <= half:
        if candn % divisor == 0:
            return(False)
        else:
            divisor += 1
    return(True)

# nextprime is meant to replace genplist
def nextprime(lastprime):
    nprime = lastprime + 2
    while True:
        if isprime(nprime):
            return(nprime)
        else:
            nprime += 2

def pffind(num):
    if isprime(num):
        return([num])
    else:
        plist = [2, 3]
        flist = []
        partial = num
        while isprime(partial) is False:
            primefactor = 0
            for prime in plist:
                if (partial % prime) == 0:
                    primefactor = prime
                    break
            if primefactor == 0:
                plist.append(nextprime(plist[-1]))
            else:
                flist.append(primefactor)
                partial = partial / primefactor
        flist.append(int(partial))
        return(flist)