diff --git a/obstools/__init__.py b/obstools/__init__.py
index e84a32b..c2af11c 100644
--- a/obstools/__init__.py
+++ b/obstools/__init__.py
@@ -8,8 +8,7 @@
 #
 #  @author: tbowers
 
-"""Init File
-"""
+"""Init File"""
 
 
 # Imports for signal and log handling
diff --git a/obstools/neocp_ephem.py b/obstools/neocp_ephem.py
index a90bf77..29c4d67 100644
--- a/obstools/neocp_ephem.py
+++ b/obstools/neocp_ephem.py
@@ -87,7 +87,7 @@
 .. warning::
 
     This module is not yet functional!
-    
+
 """
 
 # Built-In Libraries
diff --git a/obstools/scrub_deveny_pickup.py b/obstools/scrub_deveny_pickup.py
index 2b50d2c..b8a2ec0 100644
--- a/obstools/scrub_deveny_pickup.py
+++ b/obstools/scrub_deveny_pickup.py
@@ -60,7 +60,7 @@
 import ccdproc.utils.slices
 import matplotlib.pyplot as plt
 import numpy as np
-from pypeit import msgs
+from pypeit import log
 import pypeit.spec2dobj
 import scipy.fft
 import scipy.ndimage
@@ -135,7 +135,7 @@ def iterative_pypeit_clean(
         )[0]
     except (StopIteration, IndexError):
         # And... fail.
-        msgs.warn(
+        log.warning(
             f"File {filename.name} does not have a corresponding PypeIt-processed 2D spectrum. "
             "Check the image type and whether you have `run_pypeit`."
         )
@@ -1012,7 +1012,9 @@ def package_into_fits(
         suffix  (Default: False)
     """
     # Add a little history
-    time_str = datetime.datetime.utcnow().isoformat(sep=" ", timespec="seconds")
+    time_str = datetime.datetime.now(datetime.UTC).isoformat(
+        sep=" ", timespec="seconds"
+    )
     history_str = f"Written by package obstools: {time_str} UTC"
     # For the image HDUs, include a basic header
     img_hdr = astropy.io.fits.Header({"BUNIT": "ADU", "HISTORY": history_str})
diff --git a/obstools/tests/test_celestial_time.py b/obstools/tests/test_celestial_time.py
index 2f712aa..d508107 100644
--- a/obstools/tests/test_celestial_time.py
+++ b/obstools/tests/test_celestial_time.py
@@ -11,8 +11,7 @@
 #  @author: tbowers
 # pylint: disable=missing-function-docstring
 
-"""Celestial Time Utilities TEST Module
-"""
+"""Celestial Time Utilities TEST Module"""
 
 import numpy as np
 import pytest
diff --git a/obstools/tests/test_deveny_grangle.py b/obstools/tests/test_deveny_grangle.py
index 5dbdb6f..3206cf7 100644
--- a/obstools/tests/test_deveny_grangle.py
+++ b/obstools/tests/test_deveny_grangle.py
@@ -11,8 +11,7 @@
 #  @author: tbowers
 # pylint: disable=missing-function-docstring
 
-"""DeVeny Grating Angle Calculator TEST Module
-"""
+"""DeVeny Grating Angle Calculator TEST Module"""
 
 import numpy as np
 
diff --git a/obstools/tests/test_lmi_etc.py b/obstools/tests/test_lmi_etc.py
index 66d4722..8d24c67 100644
--- a/obstools/tests/test_lmi_etc.py
+++ b/obstools/tests/test_lmi_etc.py
@@ -11,8 +11,7 @@
 #  @author: tbowers
 # pylint: disable=missing-function-docstring
 
-"""LMI Exposure Time Calculator TEST Module
-"""
+"""LMI Exposure Time Calculator TEST Module"""
 
 import numpy as np
 import pytest
diff --git a/obstools/tests/test_utils.py b/obstools/tests/test_utils.py
index 52b18b0..4b538ca 100644
--- a/obstools/tests/test_utils.py
+++ b/obstools/tests/test_utils.py
@@ -11,8 +11,7 @@
 #  @author: tbowers
 # pylint: disable=missing-function-docstring
 
-"""Utility TEST Module
-"""
+"""Utility TEST Module"""
 
 from obstools import utils
 
@@ -37,7 +36,17 @@ def test_first_moment_1d():
 
 
 def test_flatten_comprehension():
-    pass
+    nested_str = [["a", "b", "c"], ["d", "e", "f"], ["g", "h", "i"]]
+    flat_str = utils.flatten_comprehension(nested_str)
+    assert flat_str == ["a", "b", "c", "d", "e", "f", "g", "h", "i"]
+    # Add other types of tests here...
+
+
+def test_flatten_itertools():
+    nested_str = [["a", "b", "c"], ["d", "e", "f"], ["g", "h", "i"]]
+    flat_str = utils.flatten_itertools(nested_str)
+    assert flat_str == ["a", "b", "c", "d", "e", "f", "g", "h", "i"]
+    # Add other types of tests here...
 
 
 def test_gaussfit():
diff --git a/obstools/utils.py b/obstools/utils.py
index 8bfc394..7c8227c 100644
--- a/obstools/utils.py
+++ b/obstools/utils.py
@@ -25,6 +25,7 @@
 import argparse
 from functools import reduce
 from importlib import resources
+import itertools
 import pathlib
 import textwrap
 import sys
@@ -139,6 +140,22 @@ def flatten_comprehension(nested_list: list[list]) -> list:
     return [item for row in nested_list for item in row]
 
 
+def flatten_itertools(nested_list: list[list]) -> list:
+    """Flatten a single-depth nested list via itertools
+
+    Parameters
+    ----------
+    nested_list : :obj:`list`
+        The single-depth nested list to flatten
+
+    Returns
+    -------
+    :obj:`list`
+        The flattened list
+    """
+    return [item for item in itertools.chain.from_iterable(nested_list)]
+
+
 def gaussfit(
     x: np.ndarray,
     y: np.ndarray,
diff --git a/setup.cfg b/setup.cfg
index ecb27ba..e7bb080 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -73,7 +73,8 @@ dev =
     sphinx_rtd_theme<3
     pylint
     black
-    pypeit[specutils]>=1.15.0
+    # pypeit[specutils]>=1.15.0
+    pypeit[specutils] @ git+https://github.com/pypeit/PypeIt.git@develop
     pyyaml
     stomp.py
     xmltodict