CLN: misc tslibs, annotations, unused imports
diff --git a/pandas/_libs/tslibs/resolution.pyx b/pandas/_libs/tslibs/resolution.pyx
index c0b20c14e9920..1e0eb7f97ec54 100644
--- a/pandas/_libs/tslibs/resolution.pyx
+++ b/pandas/_libs/tslibs/resolution.pyx
@@ -27,7 +27,7 @@ cdef:
 
 # ----------------------------------------------------------------------
 
-cpdef resolution(int64_t[:] stamps, tz=None):
+cpdef resolution(const int64_t[:] stamps, tz=None):
     cdef:
         Py_ssize_t i, n = len(stamps)
         npy_datetimestruct dts
@@ -38,7 +38,7 @@ cpdef resolution(int64_t[:] stamps, tz=None):
     return _reso_local(stamps, tz)
 
 
-cdef _reso_local(int64_t[:] stamps, object tz):
+cdef _reso_local(const int64_t[:] stamps, object tz):
     cdef:
         Py_ssize_t i, n = len(stamps)
         int reso = RESO_DAY, curr_reso
@@ -106,7 +106,7 @@ cdef inline int _reso_stamp(npy_datetimestruct *dts):
     return RESO_DAY
 
 
-def get_freq_group(freq):
+def get_freq_group(freq) -> int:
     """
     Return frequency code group of given frequency str or offset.
 
@@ -189,7 +189,7 @@ class Resolution:
     _freq_reso_map = {v: k for k, v in _reso_freq_map.items()}
 
     @classmethod
-    def get_str(cls, reso):
+    def get_str(cls, reso: int) -> str:
         """
         Return resolution str against resolution code.
 
@@ -201,7 +201,7 @@ class Resolution:
         return cls._reso_str_map.get(reso, 'day')
 
     @classmethod
-    def get_reso(cls, resostr):
+    def get_reso(cls, resostr: str) -> int:
         """
         Return resolution str against resolution code.
 
@@ -216,7 +216,7 @@ class Resolution:
         return cls._str_reso_map.get(resostr, cls.RESO_DAY)
 
     @classmethod
-    def get_freq_group(cls, resostr):
+    def get_freq_group(cls, resostr: str) -> int:
         """
         Return frequency str against resolution str.
 
@@ -228,7 +228,7 @@ class Resolution:
         return get_freq_group(cls.get_freq(resostr))
 
     @classmethod
-    def get_freq(cls, resostr):
+    def get_freq(cls, resostr: str) -> str:
         """
         Return frequency str against resolution str.
 
@@ -240,7 +240,7 @@ class Resolution:
         return cls._reso_freq_map[resostr]
 
     @classmethod
-    def get_str_from_freq(cls, freq):
+    def get_str_from_freq(cls, freq: str) -> str:
         """
         Return resolution str against frequency str.
 
@@ -252,7 +252,7 @@ class Resolution:
         return cls._freq_reso_map.get(freq, 'day')
 
     @classmethod
-    def get_reso_from_freq(cls, freq):
+    def get_reso_from_freq(cls, freq: str) -> int:
         """
         Return resolution code against frequency str.
 
diff --git a/pandas/_libs/tslibs/timedeltas.pyx b/pandas/_libs/tslibs/timedeltas.pyx
index ad7cf6ae9307d..3742506a7f8af 100644
--- a/pandas/_libs/tslibs/timedeltas.pyx
+++ b/pandas/_libs/tslibs/timedeltas.pyx
@@ -1,5 +1,4 @@
 import collections
-import textwrap
 
 import cython
 
diff --git a/pandas/_libs/tslibs/timestamps.pyx b/pandas/_libs/tslibs/timestamps.pyx
index 4915671aa6512..b8c462abe35f1 100644
--- a/pandas/_libs/tslibs/timestamps.pyx
+++ b/pandas/_libs/tslibs/timestamps.pyx
@@ -1,4 +1,3 @@
-import sys
 import warnings
 
 import numpy as np
