Fixed TypeError: Neither typeguard not pytypes is installed even with typeguard installed

docs/changelog.md

@@ -1,5 +1,10 @@
 # Changelog
 
+### 1.7.2 - bugfix
+
+ - Fixed `TypeError: Neither typeguard not pytypes is installed` even with `typeguard` installed. 
+   Fixed [#91] (https://github.com/smarie/python-pyfields/issues/91)
+
 ### 1.7.1 - Compatibility fix for typeguard `3.0.0`
 
  - Fixed `TypeError: check_type() takes 2 positional arguments but 3 were given` triggering erroneous `FieldTypeError` 

pyfields/typing_utils.py

@@ -46,9 +46,9 @@ def __str__(self):
 
 
 def _make_assert_is_of_type():
+    from packaging.version import parse as parse_version
     try:
         from typeguard import check_type as ct
-        from packaging.version import parse as parse_version
 
         # Note: only do this when we are sure that typeguard can be imported, otherwise this is slow
         # see https://github.com/smarie/python-getversion/blob/ee495acf6cf06c5e860713edeee396206368e458/getversion/main.py#L84
@@ -179,9 +179,10 @@ def assert_is_of_type(field, value, typ):
 try:  # very minimal way to check if typing it available, for runtime type checking
     # noinspection PyUnresolvedReferences
     from typing import Tuple  # noqa
-    assert_is_of_type = _make_assert_is_of_type()
 except ImportError:
     assert_is_of_type = None
+else:
+    assert_is_of_type = _make_assert_is_of_type()
 
 
 PY36 = sys.version_info >= (3, 6)

setup.cfg

@@ -32,14 +32,15 @@ classifiers =
 # one day these will be able to come from requirement files, see https://github.com/pypa/setuptools/issues/1951. But will it be better ?
 setup_requires =
     setuptools_scm
-    pytest-runner
+    # pytest-runner
 install_requires =
     valid8>=5.0
     makefun
     # note: do not use double quotes in these, this triggers a weird bug in PyCharm in debug mode only
     funcsigs;python_version<'3.3'
     enum34;python_version<'3.4'
     # 'sentinel',
+    packaging
 tests_require =
     pytest
     vtypes