title: Have python find and evaluate all decorated functions in codebase
body: <p>I'm trying to have functions in my code base that are callable by a unique identifier, for this I created a decorator that registers the function</p>
  
  <pre><code>global FUNCTION_REGISTRY
  FUNCTION_REGISTRY = {}
  
  class FunctionAlreadyRegistered(Exception):
      pass
  
  def register_function(function_identifier, function):
      global FUNCTION_REGISTRY
  
      if function_identifier not in FUNCTION_REGISTRY:
          FUNCTION_REGISTRY[function_identifier] = function
      else:
          raise FunctionAlreadyRegistered
  
  def call_registered_function(function_identifier, *args, **kwargs):
      global FUNCTION_REGISTRY
      if function_identifier in FUNCTION_REGISTRY:
          FUNCTION_REGISTRY[function_identifier](*args, **kwargs)
  
  class EventHandler(object):
      def __init__(self, identifier):
          self.identifier = identifier
  
      def __call__(self, original_func):
          decorator_self = self
  
          def wrappee(*args, **kwargs):
              original_func(*args, **kwargs)
  
          print "REGISTER FUNCTION", decorator_self.identifier
          register_function(decorator_self.identifier, wrappee)
          return wrappee
  </code></pre>
  
  <p>and then I apply this decorator like this</p>
  
  <pre><code>@EventHandler(identifier="something.task-created-handler")
  def task_created_event_handler(pk=None, *args, **kwargs):
     pass
  </code></pre>
  
  <p>this allows me to easily do the following</p>
  
  <pre><code>call_registered_function("something.task-created-handler",argument="value")
  </code></pre>
  
  <p>however this decorator is only evaluated when some other file imports this file intentionally, I'd like to evaluate all this decorator through my codebase to register all identified functions</p>
  
  <p>Is there a way to get python to evaluate all this decorators when the runtime starts in a seamless way?</p>