code: def find_tabs(self, custom_table_classes=None):
          
          for module_name in get_all_modules(self.package_path):
              for name, _type in get_all_classes(module_name):
                  # pylint: disable=W0640
                  subclasses = [Table] + (custom_table_classes or list())
                  iss_subclass = map(lambda c: issubclass(_type, c), subclasses)
                  if isclass(_type) and any(iss_subclass):
                      self.tabs.update([[name, _type]])
docs: Finds all classes that are subcalss of Table and loads them into
           a dictionary named tables.