docs: def load_class(self, classname, namespace=None):
          """
          Loads a class looking for it in each module registered. It's possible to load a class from
          specific namespace using **namespace** parameter or using classname as "namespace:classname".
  
          :param classname: Class name you want to load.
          :type classname: str
          :param namespace: Specific namespace where to look for class.
          :type namespace: str
          :return: Class object
          :rtype: type
          """
          if namespace is None and ':' in classname:
              namespace, classname = classname.split(':', 1)
              return self.load_class(classname, namespace)
          if namespace:
              if namespace not in self._namespaces:
                  raise NoRegisteredError("Namespace '{0}' is not registered on loader.".format(namespace))
              try:
                  module = importlib.import_module(self._namespaces[namespace]) \
                      if isinstance(self._namespaces[namespace], str) else self._namespaces[namespace]
  
                  return import_class(classname, module.__name__)
              except (AttributeError, ImportError):
                  raise ImportError("Class '{0}' could not be loaded from namespace '{1}'.".format(classname,
                                                                                                   namespace))
          return super(LoaderNamespace, self).load_class(classname)