修复一些BUG

将修改密码的代码逻辑做复用处理，简化代码。

utils/storage/kvstorage.py

@@ -2,11 +2,56 @@
 from __future__ import absolute_import, unicode_literals
 
 import json
+import random
+import string
+import json
+import six
 
-from dingtalk.core.utils import to_text
 from utils.storage import BaseStorage
 
 
+def to_text(value, encoding='utf-8'):
+    """Convert value to unicode, default encoding is utf-8
+
+    :param value: Value to be converted
+    :param encoding: Desired encoding
+    """
+    if not value:
+        return ''
+    if isinstance(value, six.text_type):
+        return value
+    if isinstance(value, six.binary_type):
+        return value.decode(encoding)
+    return six.text_type(value)
+
+
+def to_binary(value, encoding='utf-8'):
+    """Convert value to binary string, default encoding is utf-8
+
+    :param value: Value to be converted
+    :param encoding: Desired encoding
+    """
+    if not value:
+        return b''
+    if isinstance(value, six.binary_type):
+        return value
+    if isinstance(value, six.text_type):
+        return value.encode(encoding)
+    return to_text(value).encode(encoding)
+
+
+def random_string(length=16):
+    rule = string.ascii_letters + string.digits
+    rand_list = random.sample(rule, length)
+    return ''.join(rand_list)
+
+
+def byte2int(c):
+    if six.PY2:
+        return ord(c)
+    return c
+
+
 class KvStorage(BaseStorage):
 
     def __init__(self, kvdb, prefix='wework'):