Returns sequence of poller configurations
        
        sequence entry data structure:
            {
             'cacheablesource': cacheablesource_element, 
             'cachearea': cachearea_element
             }
        
        Returns: sequence of data structure for all poller configurations

def poller_configurations(self):
        """Returns sequence of poller configurations
        
        sequence entry data structure:
            {
             'cacheablesource': cacheablesource_element, 
             'cachearea': cachearea_element
             }
        
        Returns: sequence of data structure for all poller configurations
        """
        configs = []
        for cacheablesource in self.config.findall('cacheablesource'):
            for cachearea in self.config.findall('cachearea'):
                if 'sources' not in cachearea.attrib:
                    configs.append({'cacheablesource': cacheablesource, 
                           'cachearea': cachearea})
                elif cacheablesource.attrib['id'] in \
                                        cachearea.attrib['sources'].split():
                    configs.append({'cacheablesource': cacheablesource, 
                           'cachearea': cachearea})
        return configs