Python helpers for common cases

gistfile1.py

# I found this is a blog post several weeks ago and meant to share but have since lost the article.

# Two simple defines we can use in code to better determine what is going on without doing None checks

Omitted   = object()
Undefined = object()

# ---- Usage ---- #
# Admittedly,this is contrived but think of case where you can
# call a function with or without a value and None is allowed.
def update(self, name = Omitted, description = Omitted):
   if name is not Omitted:
      self.name = name

   if description is not Omitted:
      self.description = description

def getValue(self, key):
   # Check the cache
   value = self.cache.get(key, Undefined)
   if value is not Undefined:
      return value

   # ... build the actual value