diff --git a/imperative/python/megengine/__init__.py b/imperative/python/megengine/__init__.py
index 95f32e9ad3835f4de61a47f779e9ce328f5c5fc0..fc352f11aa84e51adb9cfdd2b6a4a4614b15c17c 100644
--- a/imperative/python/megengine/__init__.py
+++ b/imperative/python/megengine/__init__.py
@@ -76,7 +76,6 @@ from .core._imperative_rt.core2 import full_sync as _full_sync
 from .core._imperative_rt.core2 import sync as _sync
 from .core._imperative_rt.utils import _set_fork_exec_path_for_timed_func
 from .device import *
-from .dtr import *
 from .logger import enable_debug_log, get_logger, set_log_file, set_log_level
 from .serialization import load, save
 from .tensor import Parameter, Tensor, tensor
@@ -100,6 +99,7 @@ del _set_fork_exec_path_for_timed_func
 import megengine.autodiff
 import megengine.data
 import megengine.distributed
+import megengine.dtr
 import megengine.functional
 import megengine.hub
 import megengine.jit
diff --git a/imperative/python/megengine/dtr.py b/imperative/python/megengine/dtr.py
index d586b69e0f73a3faab30a15e1eb163f5fb1d8473..928a799b2ef4a3f43750339b57f4f7c39e1d77b9 100644
--- a/imperative/python/megengine/dtr.py
+++ b/imperative/python/megengine/dtr.py
@@ -11,14 +11,14 @@ from typing import Union
 
 from mprop import mproperty
 
-from .core._imperative_rt.core2 import set_option
+from .core._imperative_rt.core2 import set_option as _set_option
 from .core._imperative_rt.utils import _set_defrag
 
 _eviction_threshold = 0
 _evictee_minimum_size = 1024 ** 2
 
 
-def str2bytes(text: str) -> int:
+def _str2bytes(text: str) -> int:
     regex = re.compile(r"(\d+(?:\.\d+)?)\s*([kmg]?b)", re.IGNORECASE)
     order = ["b", "kb", "mb", "gb"]
     result = regex.findall(text)
@@ -32,7 +32,9 @@ def str2bytes(text: str) -> int:
 @mproperty
 def eviction_threshold(mod):
     r"""
-    Returns the eviction threshold in bytes.
+    Get or set the eviction threshold in bytes. It can also be set to a string,
+    whose formatting supports byte(B), kilobyte(KB), megabyte(MB) and
+    gigabyte(GB) units.
 
     .. note::
 
@@ -40,40 +42,34 @@ def eviction_threshold(mod):
        and evict resident tensors until the amount of used memory falls below
        this threshold.
 
-    """
-    return mod._eviction_threshold
-
-
-@eviction_threshold.setter
-def eviction_threshold(mod, value: Union[int, str]):
-    r"""
-    Change the eviction threshold. If `value` is an int, it represents the
-    number of bytes. If `value` is a string, its formatting supports bytes(B),
-    kilobyte(KB), megabyte(MB) and gigabyte(GB) units.
-
     Examples:
 
     .. code-block::
 
         import megengine as mge
-        mge.dtr.eviction_threshold = 2 * 1024 ** 3
         mge.dtr.eviction_threshold = "2GB"
-        mge.dtr.eviction_threshold = "2048MB"
 
     """
+    return mod._eviction_threshold
+
+
+@eviction_threshold.setter
+def eviction_threshold(mod, value: Union[int, str]):
     if isinstance(value, str):
-        mod._eviction_threshold = mod.str2bytes(value)
+        mod._eviction_threshold = mod._str2bytes(value)
     elif isinstance(value, int):
         mod._eviction_threshold = value
     else:
         raise TypeError("`value` should be a str or an int")
-    set_option("dtr_eviction_threshold", mod._eviction_threshold)
+    _set_option("dtr_eviction_threshold", mod._eviction_threshold)
 
 
 @mproperty
 def evictee_minimum_size(mod):
     r"""
-    Returns the memory threshold of tensors in bytes.
+    Get or set the memory threshold of tensors in bytes. It can also be set to a
+    string, whose formatting supports byte(B), kilobyte(KB), megabyte(MB) and
+    gigabyte(GB) units.
 
     .. note::
 
@@ -81,34 +77,26 @@ def evictee_minimum_size(mod):
        candidate set. A tensor that is not added to the candidate set will
        never be evicted during its lifetime.
 
-    """
-    return mod._evictee_minimum_size
-
-
-@evictee_minimum_size.setter
-def evictee_minimum_size(mod, value: Union[int, str]):
-    r"""
-    Change the memory threshold of tensors. If `value` is an int, it represents
-    the number of bytes. If `value` is a string, its formatting supports bytes(B),
-    kilobyte(KB), megabyte(MB) and gigabyte(GB) units.
-
     Examples:
 
     .. code-block::
 
         import megengine as mge
-        mge.dtr.evictee_minimum_size = 2 * 1024 ** 2
         mge.dtr.evictee_minimum_size = "2MB"
-        mge.dtr.evictee_minimum_size = "2048KB"
 
     """
+    return mod._evictee_minimum_size
+
+
+@evictee_minimum_size.setter
+def evictee_minimum_size(mod, value: Union[int, str]):
     if isinstance(value, str):
-        mod._evictee_minimum_size = mod.str2bytes(value)
+        mod._evictee_minimum_size = mod._str2bytes(value)
     elif isinstance(value, int):
         mod._evictee_minimum_size = value
     else:
         raise TypeError("`value` should be a str or an int")
-    set_option("dtr_evictee_minimum_size", mod._evictee_minimum_size)
+    _set_option("dtr_evictee_minimum_size", mod._evictee_minimum_size)
 
 
 def enable():
@@ -116,16 +104,16 @@ def enable():
     Enable to record computing path of tensors and to perform DTR policy.
     """
     _set_defrag(True)
-    set_option("enable_dtr_auto_drop", 1)
-    set_option("enable_drop", 1)
-    set_option("buffer_length", 0)
-    set_option("record_computing_path", 1)
+    _set_option("enable_dtr_auto_drop", 1)
+    _set_option("enable_drop", 1)
+    _set_option("buffer_length", 0)
+    _set_option("record_computing_path", 1)
 
 
 def disable():
     r"""
     Stop recording computing path of tensors and performing DTR policy.
     """
-    set_option("enable_dtr_auto_drop", 0)
-    set_option("enable_drop", 0)
-    set_option("record_computing_path", 0)
+    _set_option("enable_dtr_auto_drop", 0)
+    _set_option("enable_drop", 0)
+    _set_option("record_computing_path", 0)