Broken int conversion

intstuff.py

# data is a number from a sensor - it's either in base 10 or 16. Default is base 10, but it's sometimes 16.
# I want to return a decimal value no matter that the input base is.
# Thsi is micropython and I get this error
# ValueError: invalid syntax for integer with base 16
def uint_le(data,base = 10):
    val = struct.unpack('<H', data)
    if (base == 10):
        return (int(val[0]))
    if (base == 16):
        return int('val[0]',base)
#if line 10 reads 
# return int(val[0],base)
# I get this error instead
# TypeError: can't convert 'int' object to str implicitly