Refactor to Python3 style

qlib/data/_libs/expanding.pyx

@@ -8,7 +8,7 @@ from libc.math cimport sqrt, isnan, NAN
 from libcpp.vector cimport vector
 
 
-cdef class Expanding(object):
+cdef class Expanding:
     """1-D array expanding"""
     cdef vector[double] barv
     cdef int na_count

qlib/data/_libs/rolling.pyx

@@ -8,7 +8,7 @@ from libc.math cimport sqrt, isnan, NAN
 from libcpp.deque cimport deque
 
 
-cdef class Rolling(object):
+cdef class Rolling:
     """1-D array rolling"""
     cdef int window
     cdef deque[double] barv

qlib/data/cache.py

@@ -68,7 +68,7 @@ class MemCacheUnit(OrderedDict):
                 self.popitem(last=False)
 
 
-class MemCache(object):
+class MemCache:
     """Memory cache."""
 
     def __init__(self, mem_cache_size_limit=None, limit_type="length"):
@@ -140,7 +140,7 @@ class MemCacheExpire:
         return value, expire
 
 
-class CacheUtils(object):
+class CacheUtils:
     LOCK_ID = "QLIB"
 
     @staticmethod
@@ -224,7 +224,7 @@ class CacheUtils(object):
             current_cache_wlock.release()
 
 
-class BaseProviderCache(object):
+class BaseProviderCache:
     """Provider cache base class"""
 
     def __init__(self, provider):

qlib/data/client.py

@@ -12,7 +12,7 @@ from ..log import get_module_logger
 import pickle
 
 
-class Client(object):
+class Client:
     """A client class
 
     Provide the connection tool functions for ClientProvider.