[log] polish disable_existing_loggers (#519)

colossalai/logging/__init__.py

-from typing import List
-from .logging import DistributedLogger
 import logging
+from typing import List, Optional
 
-__all__ = ['get_dist_logger', 'DistributedLogger']
+from .logger import DistributedLogger
+
+__all__ = ['get_dist_logger', 'DistributedLogger', 'disable_existing_loggers']
 
 
 def get_dist_logger(name='colossalai'):
@@ -18,12 +19,20 @@ def get_dist_logger(name='colossalai'):
     return DistributedLogger.get_instance(name=name)
 
 
-def disable_existing_loggers(except_loggers: List[str] = ['colossalai']):
-    """Set the level of existing loggers to `WARNING`.
+def disable_existing_loggers(include: Optional[List[str]] = None, exclude: List[str] = ['colossalai']):
+    """Set the level of existing loggers to `WARNING`. By default, it will "disable" all existing loggers except the logger named "colossalai".
 
-    :param except_loggers: loggers in this `list` will be ignored when disabling, defaults to ['colossalai']
-    :type except_loggers: list, optional
+    Args:
+        include (Optional[List[str]], optional): Loggers whose name in this list will be disabled.
+            If set to `None`, `exclude` argument will be used. Defaults to None.
+        exclude (List[str], optional): Loggers whose name not in this list will be disabled.
+            This argument will be used only when `include` is None. Defaults to ['colossalai'].
     """
+    if include is None:
+        filter_func = lambda name: name not in exclude
+    else:
+        filter_func = lambda name: name in include
+
     for log_name in logging.Logger.manager.loggerDict.keys():
-        if log_name not in except_loggers:
+        if filter_func(log_name):
             logging.getLogger(log_name).setLevel(logging.WARNING)