diff --git a/pure_interface.py b/pure_interface.py
index 10fcb35..36ad611 100644
--- a/pure_interface.py
+++ b/pure_interface.py
@@ -630,7 +630,8 @@ class PureInterfaceType(abc.ABCMeta):
             raise InterfaceError('Interfaces cannot be instantiated')
         self = super(PureInterfaceType, cls).__call__(*args, **kwargs)
         for attr in cls._pi.abstractproperties:
-            if not hasattr(self, attr):
+            if not (hasattr(cls, attr) or hasattr(self, attr)):
+                # check for attribute on class first so that properties are not run.
                 raise InterfaceError('{}.__init__ does not create required attribute "{}"'.format(cls.__name__, attr))
         return self
 

Adding interface to a subclass of a subclass causes properties to be called
The following causes the `next` property to be executed when the instance is created, leading to a tb due to infinite recursion. 

```python

import pure_interface


class IA(pure_interface.PureInterface):
    next = None


class IOther(IA):
    pass


class A(object, IA):
    @property
    def next(self):
        print("next")
        return self.__class__()


class B(A):
    pass


class C(B, IOther):
    pass


C()
```
The property isn't every executed if `C` class definition is changed to either `class C(A, IOther):` or `class C(B):`.
diff --git a/tests/test_implementation_checks.py b/tests/test_implementation_checks.py
index a5442dc..6a367d3 100644
--- a/tests/test_implementation_checks.py
+++ b/tests/test_implementation_checks.py
@@ -543,6 +543,27 @@ class TestAttributeImplementations(unittest.TestCase):
 
         self.assertEqual(frozenset(), Function._pi.abstractproperties)
 
+    def test_property_not_accessed(self):
+        # previously instantiating C failed (issue 65)
+        class IA(pure_interface.PureInterface):
+            next = None
+
+        class IOther(IA):
+            pass
+
+        class A(IA, object):
+            @property
+            def next(self):
+                raise RuntimeError('property accessed')
+
+        class B(A):
+            pass
+
+        class C(B, IOther):
+            pass
+
+        C()
+
 
 class TestCrossImplementations(unittest.TestCase):
     """ test class attributes implemented as properties and vice versa """

pip install -e .[dev]
parse_log_pytest
requirements.txt
pytest
3.7
requirements.txt
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
certifi @ file:///croot/certifi_1671487769961/work/certifi
exceptiongroup==1.2.2
importlib-metadata==6.7.0
iniconfig==2.0.0
packaging==24.0
pluggy==1.2.0
-e git+https://github.com/seequent/pure_interface.git@f84be52887629ce0c3e429592ebe283a6828db40#egg=pure_interface
pytest==7.4.4
six==1.17.0
tomli==2.0.1
typing==3.7.4.3
typing_extensions==4.7.1
zipp==3.15.0

name: pure_interface
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2022.12.7=py37h06a4308_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.4.4=h6a678d5_1
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - pip=22.3.1=py37h06a4308_0
  - python=3.7.16=h7a1cb2a_0
  - readline=8.2=h5eee18b_0
  - setuptools=65.6.3=py37h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - wheel=0.38.4=py37h06a4308_0
  - xz=5.6.4=h5eee18b_1
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - exceptiongroup==1.2.2
      - importlib-metadata==6.7.0
      - iniconfig==2.0.0
      - packaging==24.0
      - pluggy==1.2.0
      - pytest==7.4.4
      - six==1.17.0
      - tomli==2.0.1
      - typing==3.7.4.3
      - typing-extensions==4.7.1
      - zipp==3.15.0
prefix: /opt/conda/envs/pure_interface

tests/test_implementation_checks.py::TestAttributeImplementations::test_property_not_accessed
tests/test_implementation_checks.py::TestImplementationChecks::test_can_override_func_with_descriptor tests/test_implementation_checks.py::TestImplementationChecks::test_can_use_type_methods tests/test_implementation_checks.py::TestImplementationChecks::test_concrete_abc_detection tests/test_implementation_checks.py::TestImplementationChecks::test_concrete_base_detection tests/test_implementation_checks.py::TestImplementationChecks::test_concrete_base_detection2 tests/test_implementation_checks.py::TestImplementationChecks::test_decorators_not_unwrapped tests/test_implementation_checks.py::TestImplementationChecks::test_instantiation_fails tests/test_implementation_checks.py::TestImplementationChecks::test_interface_abc_detection tests/test_implementation_checks.py::TestImplementationChecks::test_is_development_flag_stops_warnings tests/test_implementation_checks.py::TestImplementationChecks::test_missing_methods_warning tests/test_implementation_checks.py::TestImplementationChecks::test_partial_implementation_attribute tests/test_implementation_checks.py::TestImplementationChecks::test_partial_implementation_warning tests/test_implementation_checks.py::TestImplementationChecks::test_super_class_properties_detected tests/test_implementation_checks.py::TestPropertyImplementations::test_abstract_attribute_override_passes tests/test_implementation_checks.py::TestPropertyImplementations::test_abstract_property_is_cleared tests/test_implementation_checks.py::TestPropertyImplementations::test_abstract_property_override_passes tests/test_implementation_checks.py::TestPropertyImplementations::test_attribute_override_passes tests/test_implementation_checks.py::TestPropertyImplementations::test_class_and_static_methods tests/test_implementation_checks.py::TestPropertyImplementations::test_getattr_property_passes tests/test_implementation_checks.py::TestPropertyImplementations::test_missing_abstract_property_fails tests/test_implementation_checks.py::TestPropertyImplementations::test_missing_property_fails tests/test_implementation_checks.py::TestPropertyImplementations::test_missing_property_subclass_fails tests/test_implementation_checks.py::TestPropertyImplementations::test_property_override_passes tests/test_implementation_checks.py::TestPropertyImplementations::test_ro_abstract_attribute_override_passes tests/test_implementation_checks.py::TestPropertyImplementations::test_ro_abstract_attribute_override_passes3 tests/test_implementation_checks.py::TestPropertyImplementations::test_ro_abstract_property_override_passes tests/test_implementation_checks.py::TestPropertyImplementations::test_ro_abstract_property_override_passes3 tests/test_implementation_checks.py::TestPropertyImplementations::test_ro_attribute_override_passes tests/test_implementation_checks.py::TestPropertyImplementations::test_ro_property_override_passes tests/test_implementation_checks.py::TestAttributeImplementations::test_attr_overridden_with_func tests/test_implementation_checks.py::TestAttributeImplementations::test_class_attribute_in_dir tests/test_implementation_checks.py::TestAttributeImplementations::test_class_attribute_in_interface tests/test_implementation_checks.py::TestAttributeImplementations::test_class_attribute_is_removed tests/test_implementation_checks.py::TestAttributeImplementations::test_class_attribute_is_required tests/test_implementation_checks.py::TestAttributeImplementations::test_class_attribute_must_be_none tests/test_implementation_checks.py::TestAttributeImplementations::test_class_attribute_passes tests/test_implementation_checks.py::TestAttributeImplementations::test_instance_attribute_passes tests/test_implementation_checks.py::TestAttributeImplementations::test_mock_spec_includes_attrs tests/test_implementation_checks.py::TestAttributeImplementations::test_property_passes tests/test_implementation_checks.py::TestAttributeImplementations::test_raising_property tests/test_implementation_checks.py::TestCrossImplementations::test_cross_implementations
pure_interface.py
pure_interface.py