add the specific exception message for CBH

Author: natmokval

pandas/core/indexes/datetimes.py

@@ -1134,11 +1134,13 @@ def bdate_range(
         raise TypeError(msg)
 
     if isinstance(freq, str) and freq.upper().startswith("C"):
+        msg = f"invalid custom frequency string: {freq}"
+        if freq == "CBH":
+            raise ValueError(f"{msg}, did you mean cbh?")
         try:
             weekmask = weekmask or "Mon Tue Wed Thu Fri"
             freq = prefix_mapping[freq](holidays=holidays, weekmask=weekmask)
         except (KeyError, TypeError) as err:
-            msg = f"invalid custom frequency string: {freq}"
             raise ValueError(msg) from err
     elif holidays or weekmask:
         msg = (

pandas/tests/indexes/datetimes/test_date_range.py

@@ -1305,6 +1305,14 @@ def test_cdaterange_cbh(self):
         )
         tm.assert_index_equal(result, expected)
 
+    def test_cdaterange_deprecated_error_CBH(self):
+        # GH#62849
+        msg = "invalid custom frequency string: CBH, did you mean cbh?"
+        with pytest.raises(ValueError, match=msg):
+            bdate_range(
+                START, END, freq="CBH", weekmask="Mon Wed Fri", holidays=["2009-03-14"]
+            )
+
 
 class TestDateRangeNonNano:
     def test_date_range_reso_validation(self):