SEDOL

Whilst browsing Rosetta Code, I came across a good algorithm for training students, SEDOL, so coded up a version in what I would call a very litteral translation of  itsexplanation.
I changed the Python example on Wikipedia, as it did not have a validation function as other examples have, and added my code to the Rosetta page.

'''
From: http://en.wikipedia.org/wiki/SEDOL
SEDOLs are seven characters in length, consisting of two parts:
 a six-place alphanumeric code and a trailing check digit. 
'''
import string
# constants
sedolchars = string.digits + string.ascii_uppercase
sedol2value = dict((ch, n) for n,ch in enumerate(sedolchars))
for ch in 'AEIOU':
    del sedol2value[ch]
sedolchars = sorted(sedol2value.keys())
sedolweight = [1,3,1,7,3,9,1]
def check(sedol):
    return len(sedol) == 7 and \
          &nbspall(ch in sedolchars for ch in sedol) and \
          &nbspsum(sedol2value[ch] * sedolweight[n]
               for n,ch in enumerate(sedol)
               ) % 10 == 0
def checksum(sedol):
   &nbsptmp = sum(sedol2value[ch] * sedolweight[n]
               for n,ch in enumerate(sedol[:6])
               )
    return sedolchars[ (10 - (tmp % 10)) % 10]

sedol = '0263494'
print sedol, checksum(sedol)
print
# From: http://www.rosettacode.org/wiki/SEDOL
for sedol in '''
 710889
 B0YBKJ
 406566
 B0YBLH
 228276
 B0YBKL
 557910
 B0YBKR
 585284
 B0YBKT
 '''.split():
    print sedol + checksum(sedol)

Note:
 I came back to the code after a few hours of sleep and thought initially that I would have trouble in the return statement of  checksum() as I thought I would need a dictionary doing the full reverse matching of what sedol2value, from ints to characters. sedolchars nolonger includes the vowels so using that method for a value over 9 will not work.
Luckily, the result of the calculation is always in the range 0<= n >=9, and within that range, sedolchars[n] works.