added doc-string

Author: anmyachev

pandas/_libs/tslibs/conversion.pyx

@@ -393,23 +393,42 @@ cdef _TSObject convert_datetime_to_tsobject(datetime ts, object tz,
     return obj
 
 
-cdef _TSObject setup_tsobject_tz_using_offset(_TSObject obj,
-                                              object tz, int tzoffset):
-    obj.tzinfo = pytz.FixedOffset(tzoffset)
-    obj.value = tz_convert_single(obj.value, obj.tzinfo, UTC)
+cdef _TSObject create_tsobject_tz_using_offset(int64_t value,
+                                               object tz, int tzoffset):
+    """
+    Create tsobject from numpy datetime64 using initial timezone offset
+
+    Parameters
+    ----------
+    value: int64_t
+        numpy dt64
+    tz : tzinfo or None
+        timezone for the timezone-aware output.
+    tzoffset: int
+
+    Returns
+    obj : _TSObject
+    -------
+
+    """
+    cdef:
+        _TSObject obj
+        datetime dt
+
+    tzinfo = pytz.FixedOffset(tzoffset)
+    value = tz_convert_single(value, tzinfo, UTC)
+    obj = convert_to_tsobject(value, tzinfo, None, 0, 0)
     if tz is None:
         check_overflows(obj)
         return obj
-    else:
-        # Keep the converter same as PyDateTime's
-        obj = convert_to_tsobject(obj.value, obj.tzinfo,
-                                  None, 0, 0)
-        dt = datetime(obj.dts.year, obj.dts.month, obj.dts.day,
-                      obj.dts.hour, obj.dts.min, obj.dts.sec,
-                      obj.dts.us, obj.tzinfo)
-        obj = convert_datetime_to_tsobject(
-            dt, tz, nanos=obj.dts.ps // 1000)
-        return obj
+
+    # Keep the converter same as PyDateTime's
+    dt = datetime(obj.dts.year, obj.dts.month, obj.dts.day,
+                  obj.dts.hour, obj.dts.min, obj.dts.sec,
+                  obj.dts.us, obj.tzinfo)
+    obj = convert_datetime_to_tsobject(
+        dt, tz, nanos=obj.dts.ps // 1000)
+    return obj
 
 
 cdef _TSObject convert_str_to_tsobject(object ts, object tz, object unit,
@@ -440,16 +459,14 @@ cdef _TSObject convert_str_to_tsobject(object ts, object tz, object unit,
     obj : _TSObject
     """
     cdef:
-        _TSObject obj
+        npy_datetimestruct dts
+        int64_t value  # numpy dt64
         int out_local = 0, out_tzoffset = 0
-        datetime dt
         bint do_parse_datetime_string = False
 
     if tz is not None:
         tz = maybe_get_tz(tz)
 
-    obj = _TSObject()
-
     assert isinstance(ts, str)
 
     if len(ts) == 0 or ts in nat_strings:
@@ -465,18 +482,18 @@ cdef _TSObject convert_str_to_tsobject(object ts, object tz, object unit,
         # equiv: datetime.today().replace(tzinfo=tz)
     else:
         string_to_dts_failed = _string_to_dts(
-            ts, &obj.dts, &out_local,
+            ts, &dts, &out_local,
             &out_tzoffset, False
         )
         try:
             if not string_to_dts_failed:
-                check_dts_bounds(&obj.dts)
-                obj.value = dtstruct_to_dt64(&obj.dts)
+                check_dts_bounds(&dts)
+                value = dtstruct_to_dt64(&dts)
                 if out_local == 1:
-                    return setup_tsobject_tz_using_offset(obj, tz,
-                                                          out_tzoffset)
+                    return create_tsobject_tz_using_offset(value, tz,
+                                                           out_tzoffset)
                 else:
-                    ts = obj.value
+                    ts = value
                     if tz is not None:
                         # shift for localize_tso
                         ts = tz_localize_to_utc(np.array([ts], dtype='i8'), tz,