move functions is_in_valid_relative_index_types and is_in_valid_absol…

…ute_index_types to utils/validation/series.py

sktime/forecasting/base/_fh.py

@@ -22,14 +22,11 @@
 )
 from sktime.utils.validation.series import (
     VALID_INDEX_TYPES,
+    is_in_valid_absolute_index_types,
     is_in_valid_index_types,
-    is_integer_index,
+    is_in_valid_relative_index_types,
 )
 
-RELATIVE_TYPES = (pd.RangeIndex, pd.TimedeltaIndex)
-ABSOLUTE_TYPES = (pd.RangeIndex, pd.DatetimeIndex, pd.PeriodIndex)
-assert set(RELATIVE_TYPES).issubset(VALID_INDEX_TYPES)
-assert set(ABSOLUTE_TYPES).issubset(VALID_INDEX_TYPES)
 VALID_FORECASTING_HORIZON_TYPES = (int, list, np.ndarray, pd.Index)
 
 DELEGATED_METHODS = (
@@ -59,14 +56,6 @@
 )
 
 
-def is_relative_fh_type(values) -> bool:
-    return type(values) in RELATIVE_TYPES or is_integer_index(values)
-
-
-def is_absolute_fh_type(values) -> bool:
-    return type(values) in ABSOLUTE_TYPES or is_integer_index(values)
-
-
 def _delegator(method):
     """Automatically decorate ForecastingHorizon class with pandas.Index methods.
 
@@ -194,17 +183,17 @@ def __init__(
         # types inherit from each other, hence we check for type equality
         error_msg = f"`values` type is not compatible with `is_relative={is_relative}`."
         if is_relative is None:
-            if is_relative_fh_type(values):
+            if is_in_valid_relative_index_types(values):
                 is_relative = True
-            elif is_absolute_fh_type(values):
+            elif is_in_valid_absolute_index_types(values):
                 is_relative = False
             else:
                 raise TypeError(f"{type(values)} is not a supported fh index type")
         if is_relative:
-            if not is_relative_fh_type(values):
+            if not is_in_valid_relative_index_types(values):
                 raise TypeError(error_msg)
         else:
-            if not is_absolute_fh_type(values):
+            if not is_in_valid_absolute_index_types(values):
                 raise TypeError(error_msg)
 
         self._values = values

sktime/utils/validation/series.py

@@ -25,13 +25,30 @@
     pd.DatetimeIndex,
     pd.TimedeltaIndex,
 )
+RELATIVE_INDEX_TYPES = (pd.RangeIndex, pd.TimedeltaIndex)
+ABSOLUTE_INDEX_TYPES = (pd.RangeIndex, pd.DatetimeIndex, pd.PeriodIndex)
+assert set(RELATIVE_INDEX_TYPES).issubset(VALID_INDEX_TYPES)
+assert set(ABSOLUTE_INDEX_TYPES).issubset(VALID_INDEX_TYPES)
+
+
+def is_integer_index(x) -> bool:
+    """Check that the input is an integer pd.Index."""
+    return isinstance(x, pd.Index) and x.is_integer()
 
 
 def is_in_valid_index_types(x) -> bool:
     """Check that the input type belongs to the valid index types."""
     return isinstance(x, VALID_INDEX_TYPES) or is_integer_index(x)
 
 
+def is_in_valid_relative_index_types(x) -> bool:
+    return isinstance(x, RELATIVE_INDEX_TYPES) or is_integer_index(x)
+
+
+def is_in_valid_absolute_index_types(x) -> bool:
+    return isinstance(x, ABSOLUTE_INDEX_TYPES) or is_integer_index(x)
+
+
 def _check_is_univariate(y, var_name="input"):
     """Check if series is univariate."""
     if isinstance(y, pd.DataFrame):
@@ -279,11 +296,6 @@ def check_equal_time_index(*ys, mode="equal"):
             raise ValueError(msg)
 
 
-def is_integer_index(x) -> bool:
-    """Check that the input is an integer pd.Index."""
-    return isinstance(x, pd.Index) and x.is_integer()
-
-
 def check_consistent_index_type(a, b):
     """Check that two indices have consistent types.