Python typechecker

Hi,
I have found a way to solve this.
I'm not sure it does not add another bug somewhere else but
it works for me.
In the file typeclasses.py, I have changed this:

### Number
####################################################

_numbers = [int, float, complex, long, bool]
try:
from decimal import Decimal
_numbers.append(Decimal)
del Decimal
except ImportError:
pass
del _numbers

to this:

from typecheck import IsOneOf
### Number
####################################################

try:
from decimal import Decimal
Number = IsOneOf(int, float, long, complex, Decimal)
del Decimal
except ImportError:
Number = IsOneOf(int, float, long, complex)

I will do the same for String, etc.

Regards,
Marc.