diff --git a/pandas_ta/momentum/squeeze.py b/pandas_ta/momentum/squeeze.py
index 4a4525a..b5a2a09 100644
--- a/pandas_ta/momentum/squeeze.py
+++ b/pandas_ta/momentum/squeeze.py
@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 from numpy import NaN as npNaN
-from pandas import concat, DataFrame
+from pandas import DataFrame
 
 from pandas_ta.momentum import mom
 from pandas_ta.overlap import ema, linreg, sma
diff --git a/pandas_ta/utils/_math.py b/pandas_ta/utils/_math.py
index 149ed7a..2779aed 100644
--- a/pandas_ta/utils/_math.py
+++ b/pandas_ta/utils/_math.py
@@ -177,8 +177,7 @@ def df_error_analysis(dfA: DataFrame, dfB: DataFrame, **kwargs) -> DataFrame:
 
 # PRIVATE
 def _linear_regression_np(x: Series, y: Series) -> dict:
-    """Simple Linear Regression in Numpy for two 1d arrays for environments
-    without the sklearn package."""
+    """Simple Linear Regression in Numpy for two 1d arrays for environments without the sklearn package."""
     m = x.size
     x_sum = x.sum()
     y_sum = y.sum()
diff --git a/pandas_ta/utils/_signals.py b/pandas_ta/utils/_signals.py
index 0408d22..18b71e0 100644
--- a/pandas_ta/utils/_signals.py
+++ b/pandas_ta/utils/_signals.py
@@ -92,8 +92,7 @@ def cross(series_a: Series, series_b: Series, above: bool = True, asint: bool =
     return cross
 
 
-def signals(indicator, xa, xb, cross_values, xserie, xserie_a, xserie_b,
-            cross_series, offset) -> DataFrame:
+def signals(indicator, xa, xb, cross_values, xserie, xserie_a, xserie_b, cross_series, offset) -> DataFrame:
     df = DataFrame()
     if xa is not None and isinstance(xa, (int, float)):
         if cross_values:
diff --git a/tests/test_utils_metrics.py b/tests/test_utils_metrics.py
index 1daa7bd..db6233b 100644
--- a/tests/test_utils_metrics.py
+++ b/tests/test_utils_metrics.py
@@ -3,6 +3,7 @@ from .context import pandas_ta
 
 from unittest import skip, TestCase
 
+from numpy import nan as npNaN
 from pandas import DataFrame