allowing Configuration to use a pydantic class type instead of instance

src/dependency_injector/providers.pyx

@@ -157,10 +157,7 @@ cdef dict pydantic_settings_to_dict(settings, dict kwargs):
         )
 
     if isinstance(settings, type) and issubclass(settings, PydanticSettings):
-        raise Error(
-            "Got settings class, but expect instance: "
-            "instead \"{0}\" use \"{0}()\"".format(settings.__name__)
-        )
+        settings = settings()
 
     if not isinstance(settings, PydanticSettings):
         raise Error(

tests/unit/providers/configuration/test_from_pydantic_py36.py

@@ -168,21 +168,23 @@ def test_option_not_instance_of_settings(config):
 
 
 def test_subclass_instead_of_instance(config):
-    with raises(errors.Error) as error:
-        config.from_pydantic(Settings1)
-    assert error.value.args[0] == (
-        "Got settings class, but expect instance: "
-        "instead \"Settings1\" use \"Settings1()\""
-    )
+    config.from_pydantic(Settings1)
+
+    assert config() == {"section1": {"value1": 1}, "section2": {"value2": 2}}
+    assert config.section1() == {"value1": 1}
+    assert config.section1.value1() == 1
+    assert config.section2() == {"value2": 2}
+    assert config.section2.value2() == 2
 
 
 def test_option_subclass_instead_of_instance(config):
-    with raises(errors.Error) as error:
-        config.option.from_pydantic(Settings1)
-    assert error.value.args[0] == (
-        "Got settings class, but expect instance: "
-        "instead \"Settings1\" use \"Settings1()\""
-    )
+    config.option.from_pydantic(Settings1)
+
+    assert config.option() == {"section1": {"value1": 1}, "section2": {"value2": 2}}
+    assert config.option.section1() == {"value1": 1}
+    assert config.option.section1.value1() == 1
+    assert config.option.section2() == {"value2": 2}
+    assert config.option.section2.value2() == 2
 
 
 @mark.usefixtures("no_pydantic_module_installed")