From 1bb0b605d9a254e99c78a7b98bfea938bca95e7b Mon Sep 17 00:00:00 2001
From: Nate Parsons <4307001+thehomebrewnerd@users.noreply.github.com>
Date: Wed, 1 May 2024 17:07:22 -0500
Subject: [PATCH] Move flatten_list util function into feature_discovery
 (#2702)

* move util func

* update release notes

* remove dask restriction

* update release notes
---
 docs/source/release_notes.rst                               | 1 +
 featuretools/feature_discovery/feature_discovery.py         | 3 +--
 featuretools/feature_discovery/utils.py                     | 4 ++++
 featuretools/tests/testing_utils/generate_fake_dataframe.py | 6 ++----
 4 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/docs/source/release_notes.rst b/docs/source/release_notes.rst
index ddaf5aecc6..8370fa29e4 100644
--- a/docs/source/release_notes.rst
+++ b/docs/source/release_notes.rst
@@ -7,6 +7,7 @@ Future Release
 ==============
     * Enhancements
     * Fixes
+        * Move ``flatten_list`` util function into ``feature_discovery`` module to fix import bug (:pr:`2702`)
     * Changes
         * Temporarily restrict Dask version (:pr:`2694`)
         * Remove support for creating ``EntitySets`` from Dask or Pyspark dataframes (:pr:`2705`)
diff --git a/featuretools/feature_discovery/feature_discovery.py b/featuretools/feature_discovery/feature_discovery.py
index 36826b056c..46fb575c1e 100644
--- a/featuretools/feature_discovery/feature_discovery.py
+++ b/featuretools/feature_discovery/feature_discovery.py
@@ -9,9 +9,8 @@
 
 from featuretools.feature_discovery.FeatureCollection import FeatureCollection
 from featuretools.feature_discovery.LiteFeature import LiteFeature
-from featuretools.feature_discovery.utils import column_schema_to_keys
+from featuretools.feature_discovery.utils import column_schema_to_keys, flatten_list
 from featuretools.primitives.base.primitive_base import PrimitiveBase
-from featuretools.tests.testing_utils.generate_fake_dataframe import flatten_list
 
 
 def _index_column_set(column_set: List[ColumnSchema]) -> List[Tuple[str, int]]:
diff --git a/featuretools/feature_discovery/utils.py b/featuretools/feature_discovery/utils.py
index 01d942e596..ed334c29c2 100644
--- a/featuretools/feature_discovery/utils.py
+++ b/featuretools/feature_discovery/utils.py
@@ -75,3 +75,7 @@ def get_primitive_return_type(primitive: PrimitiveBase) -> ColumnSchema:
     if isinstance(return_type, list):
         return_type = return_type[0]
     return return_type
+
+
+def flatten_list(nested_list):
+    return [item for sublist in nested_list for item in sublist]
diff --git a/featuretools/tests/testing_utils/generate_fake_dataframe.py b/featuretools/tests/testing_utils/generate_fake_dataframe.py
index 5b39ecf6d7..96112a515c 100644
--- a/featuretools/tests/testing_utils/generate_fake_dataframe.py
+++ b/featuretools/tests/testing_utils/generate_fake_dataframe.py
@@ -5,6 +5,8 @@
 import woodwork.type_sys.type_system as ww_type_system
 from woodwork import logical_types
 
+from featuretools.feature_discovery.utils import flatten_list
+
 logical_type_mapping = {
     logical_types.Boolean.__name__: [True, False],
     logical_types.BooleanNullable.__name__: [True, False, pd.NA],
@@ -31,10 +33,6 @@
 }
 
 
-def flatten_list(nested_list):
-    return [item for sublist in nested_list for item in sublist]
-
-
 def generate_fake_dataframe(
     col_defs=[("f_1", "Numeric"), ("f_2", "Datetime", "time_index")],
     n_rows=10,