diff --git a/src/spikeinterface/extractors/neoextractors/neuroscope.py b/src/spikeinterface/extractors/neoextractors/neuroscope.py
index 801b9c1928..c652ce4fb9 100644
--- a/src/spikeinterface/extractors/neoextractors/neuroscope.py
+++ b/src/spikeinterface/extractors/neoextractors/neuroscope.py
@@ -9,12 +9,6 @@
 
 from .neobaseextractor import NeoBaseRecordingExtractor
 
-try:
-    from lxml import etree as et
-
-    HAVE_LXML = True
-except ImportError:
-    HAVE_LXML = False
 
 PathType = Union[str, Path]
 OptionalPathType = Optional[PathType]
@@ -108,8 +102,6 @@ class NeuroScopeSortingExtractor(BaseSorting):
     """
 
     extractor_name = "NeuroscopeSortingExtractor"
-    installed = HAVE_LXML
-    installation_mesg = "Please install lxml to use this extractor!"
     name = "neuroscope"
 
     def __init__(
@@ -121,7 +113,7 @@ def __init__(
         exclude_shanks: Optional[list] = None,
         xml_file_path: OptionalPathType = None,
     ):
-        assert self.installed, self.installation_mesg
+        from lxml import etree as et
 
         assert not (
             folder_path is None and resfile_path is None and clufile_path is None
diff --git a/src/spikeinterface/postprocessing/template_metrics.py b/src/spikeinterface/postprocessing/template_metrics.py
index 3f47c505ad..bd6d1eff2a 100644
--- a/src/spikeinterface/postprocessing/template_metrics.py
+++ b/src/spikeinterface/postprocessing/template_metrics.py
@@ -3,6 +3,8 @@
 https://github.com/AllenInstitute/ecephys_spike_sorting/blob/master/ecephys_spike_sorting/modules/mean_waveforms/waveform_metrics.py
 22/04/2020
 """
+from __future__ import annotations
+
 import numpy as np
 import warnings
 from typing import Optional