[BioPython] name 'Select' is not defined

[Hua Wong]

I've been through all the operations I wanted (thank you Thomas) but now
I am stuck while doing the output of the pdb.

I looked at the FAQ and the example with the gly.
I tried first by myself:
class ChainSelect(Select):
	def accept_chain(self,chain):
		if chain.get_id()=='A':
			return 1
		else:
			return 0

then as it displays :
Traceback (most recent call last):
  File "/home/pif/wong/snafuscripts/pdbmoomoo.py", line 135, in ?
    class ChainSelect(Select):
NameError: name 'Select' is not defined

I tried the example from the FAQ:
class ChainSelect(Select):
	def accept_residue(self,residue):
		if residue.get_name()=='GLY':
			return 1
		else:
			return 0

But it displays the same error.
NameError: name 'Select' is not defined

What is it all about? What can I do about this?

Thanks