switch to dateutil, it's much more lightweight

.pre-commit-config.yaml

@@ -26,4 +26,4 @@ repos:
         entry: pylint
         language: python
         types: [python]
-        additional_dependencies: [beautifulsoup4, pylint, requests, adafruit-circuitpython-datetime, click, dateparser]
+        additional_dependencies: [beautifulsoup4, pylint, requests, adafruit-circuitpython-datetime, click, python-dateutil]

README.md

@@ -64,7 +64,7 @@ channel.
 # Usage
 
 ~~~~
-Usage: wwvbgen.py [options] [dateparser-string | year yday hour minute | year month day hour minute]
+Usage: wwvbgen.py [options] [dateutil-string | year yday hour minute | year month day hour minute]
 
 Options:
   -h, --help            show this help message and exit

requirements-dev.txt

@@ -6,8 +6,8 @@ beautifulsoup4
 build
 click
 coverage
-dateparser
 pre-commit
+python-dateutil
 requests
 setuptools>=42
 twine

requirements.txt

@@ -3,4 +3,4 @@
 # SPDX-License-Identifier: GPL-3.0-only
 adafruit-circuitpython-datetime
 click
-dateparser
+python-dateutil

wwvb/gen.py

@@ -10,6 +10,8 @@ import datetime
 import sys
 import click
 
+import dateutil.parser
+
 from . import (
     print_timecodes,
     WWVBMinute,
@@ -30,10 +32,7 @@ def parse_timespec(ctx, param, value):  # pylint: disable=unused-argument
                 days=yday
             )
         if len(value) == 1:
-            # dateparser is slow to import (>300ms on i5-3320M) so postpone it
-            import dateparser  # pylint: disable=import-outside-toplevel
-
-            return dateparser.parse(value[0])
+            return dateutil.parser.parse(value[0])
         if len(value) == 0:
             return datetime.datetime.utcnow()
         raise ValueError("Unexpected number of arguments")