Counting Number of Prime Forms

def strtoval(s):
    val=0
    pow=1
    for i in reversed(range(len(s))):
        if s[i]=='1':
            val += pow
        pow *= 2
    return val

def settostr(setex,n):
    str=""
    for i in range(n):
       if i in setex:
           str += '1'
       else:
           str += '0'
    return str

def isprimeform(str):
    teststr=str[:]
    val = strtoval(str)
    for i in range(len(str)-1):
        teststr = teststr[1:] + teststr[0]
        if strtoval(teststr) > val:
            return False
    teststr=str[::-1]
    for i in range(len(str)-1):
        teststr = teststr[1:] + teststr[0]
        if strtoval(teststr) > val:
            return False
    return True


import time
start = time.time()
import itertools
n = 12
iterable = range(0, n)
pcsetslist = [list(itertools.combinations(iterable,i)) for i in range(0,n + 1)]
pcsets = list(itertools.chain(*pcsetslist))

count=0
for set in pcsets:
    if isprimeform(settostr(set,n)):
        print(set)
        count += 1

print("Count of number of prime forms:", count)
print(str(time.time() - start) + ' seconds')