Add is_featured boolean property to the Work model, so that Works can be
designated as "featured" items in various places in the UI. This will be
used to allow Sponsors, Programs, and Organizations to select Documents that
should be included in their sidebar menus.
Perhaps featured "site" Documents, such as site-wide Terms of Service,
should probably be listed below the "User (sign-out)" menu, since the User
will have to read and agree to these before being allowed to use the site.
A collapsable Javascript sidebar is probably going to be needed soon...
Patch by: Todd Larsen
Review by: to-be-reviewed
"""
Common checksum routines (used in multiple localflavor/ cases, for example).
"""
__all__ = ['luhn',]
LUHN_ODD_LOOKUP = (0, 2, 4, 6, 8, 1, 3, 5, 7, 9) # sum_of_digits(index * 2)
def luhn(candidate):
"""
Checks a candidate number for validity according to the Luhn
algorithm (used in validation of, for example, credit cards).
Both numeric and string candidates are accepted.
"""
if not isinstance(candidate, basestring):
candidate = str(candidate)
try:
evens = sum([int(c) for c in candidate[-1::-2]])
odds = sum([LUHN_ODD_LOOKUP[int(c)] for c in candidate[-2::-2]])
return ((evens + odds) % 10 == 0)
except ValueError: # Raised if an int conversion fails
return False