def changebase(n, base=10, to=10):
'''
params:
n - number to convert
base - current base of number 'n'
to - desired base, must be <= 36
'''
# check that new base is <= 36
if to > 36 or base > 36:
raise ValueError('max base is 36')
# convert to base 10
n = int(str(n), base)
positive = n >= 0
# return if base 10 is desired
if to == 10:
return str(n)
# convert to new base
n = abs(n)
num = []
handle_digit = lambda n: str(n) if n < 10 else chr(n + 55)
while n > 0:
num.insert(0, handle_digit(n % to))
n = n // to
# return string value of n in new base
return ''.join(num) if positive else '-' + ''.join(num)
print(changebase('22', 4, 2)) # decimal=10, base-4=22, base-2=1010
