fix: change to type instead of instantiated type

src/timeseriesflattener/aggregators.py

@@ -11,7 +11,7 @@ def _validate_compatible_fallback_type_for_aggregator(
     aggregator: Aggregator, fallback: str | int | float | None
 ) -> None:
     try:
-        pl.Series([aggregator.output_type]).fill_null(fallback)
+        pl.Series([aggregator.output_type()]).fill_null(fallback)
     except:
         raise ValueError(
             f"Invalid fallback value {fallback} for aggregator {aggregator.__class__.__name__}. Fallback of type {type(fallback)} is not compatible with the aggregator's output type of {type(aggregator.output_type)}."
@@ -20,7 +20,7 @@ def _validate_compatible_fallback_type_for_aggregator(
 
 class Aggregator(ABC):
     name: str
-    output_type: float | int | bool
+    output_type: type[float | int | bool]
 
     @abstractmethod
     def __call__(self, column_name: str) -> pl.Expr:
@@ -34,7 +34,7 @@ class MinAggregator(Aggregator):
     """Returns the minimum value in the look window."""
 
     name: str = "min"
-    output_type = float()
+    output_type = float
 
     def __call__(self, column_name: str) -> pl.Expr:
         return pl.col(column_name).min().alias(self.new_col_name(column_name))
@@ -44,7 +44,7 @@ class MaxAggregator(Aggregator):
     """Returns the maximum value in the look window."""
 
     name: str = "max"
-    output_type = float()
+    output_type = float
 
     def __call__(self, column_name: str) -> pl.Expr:
         return pl.col(column_name).max().alias(self.new_col_name(column_name))
@@ -54,7 +54,7 @@ class MeanAggregator(Aggregator):
     """Returns the mean value in the look window."""
 
     name: str = "mean"
-    output_type = float()
+    output_type = float
 
     def __call__(self, column_name: str) -> pl.Expr:
         return pl.col(column_name).mean().alias(self.new_col_name(column_name))
@@ -64,7 +64,7 @@ class CountAggregator(Aggregator):
     """Returns the count of non-null values in the look window."""
 
     name: str = "count"
-    output_type = int()
+    output_type = int
 
     def __call__(self, column_name: str) -> pl.Expr:
         return pl.col(column_name).count().alias(self.new_col_name(column_name))
@@ -76,7 +76,7 @@ class EarliestAggregator(Aggregator):
 
     timestamp_col_name: str
     name: str = "earliest"
-    output_type = float()
+    output_type = float
 
     def __call__(self, column_name: str) -> pl.Expr:
         return (
@@ -93,7 +93,7 @@ class LatestAggregator(Aggregator):
 
     timestamp_col_name: str
     name: str = "latest"
-    output_type = float()
+    output_type = float
 
     def __call__(self, column_name: str) -> pl.Expr:
         return (
@@ -108,7 +108,7 @@ class SumAggregator(Aggregator):
     """Returns the sum of all values in the look window."""
 
     name: str = "sum"
-    output_type = float()
+    output_type = float
 
     def __call__(self, column_name: str) -> pl.Expr:
         return pl.col(column_name).sum().alias(self.new_col_name(column_name))
@@ -118,7 +118,7 @@ class VarianceAggregator(Aggregator):
     """Returns the variance of the values in the look window"""
 
     name: str = "var"
-    output_type = float()
+    output_type = float
 
     def __call__(self, column_name: str) -> pl.Expr:
         return pl.col(column_name).var().alias(self.new_col_name(column_name))
@@ -128,7 +128,7 @@ class HasValuesAggregator(Aggregator):
     """Examines whether any values exist in the column. If so, returns True, else False."""
 
     name: str = "bool"
-    output_type = bool()
+    output_type = bool
 
     def __call__(self, column_name: str) -> pl.Expr:
         return (
@@ -147,7 +147,7 @@ class SlopeAggregator(Aggregator):
 
     timestamp_col_name: str
     name: str = "slope"
-    output_type = float()
+    output_type = float
 
     def __call__(self, column_name: str) -> pl.Expr:
         # Convert to days for the slope. Arbitrarily chosen to be the number of days since 1970-01-01.