diff --git a/exasol_integration_test_docker_environment/doctor.py b/exasol_integration_test_docker_environment/doctor.py
index 5640a8006..4fe8bc21b 100644
--- a/exasol_integration_test_docker_environment/doctor.py
+++ b/exasol_integration_test_docker_environment/doctor.py
@@ -3,7 +3,8 @@
 package and also provide help to find potential fixes.
 """
 import sys
-from typing import Iterable
+from collections.abc import Callable
+from typing import Iterable, List, Tuple
 from exasol import error
 from enum import Enum
 
@@ -78,11 +79,13 @@ def health_checkup() -> Iterable[error.ExaError]:
 
     return an iterator of error codes specifying which problems have been identified.
     """
-    examinations = [
+    check_function = Callable[[],bool]
+    diagnosis_function = Callable[[],Iterable[error.ExaError]]
+    examinations : List[Tuple[check_function, diagnosis_function]] = [
         (is_docker_daemon_available, diagnose_docker_daemon_not_available),
-        (is_supported_platform, lambda: Error.TargetPlatformNotSupported),
+        (is_supported_platform, lambda: [Error.TargetPlatformNotSupported]),
     ]
     for is_fine, diagnosis in examinations:
         if not is_fine():
-            for error_code in diagnosis(): # type: ignore
+            for error_code in diagnosis():
                 yield error_code
diff --git a/exasol_integration_test_docker_environment/lib/api/common.py b/exasol_integration_test_docker_environment/lib/api/common.py
index bff85d6f7..6d93671da 100644
--- a/exasol_integration_test_docker_environment/lib/api/common.py
+++ b/exasol_integration_test_docker_environment/lib/api/common.py
@@ -104,8 +104,9 @@ def import_build_steps(flavor_path: Tuple[str, ...]):
         path_to_build_steps = Path(path).joinpath("flavor_base/build_steps.py")
         module_name_for_build_steps = extract_modulename_for_build_steps(path)
         spec = importlib.util.spec_from_file_location(module_name_for_build_steps, path_to_build_steps)
-        module = importlib.util.module_from_spec(spec) # type: ignore
-        spec.loader.exec_module(module) # type: ignore
+        assert spec and spec.loader
+        module = importlib.util.module_from_spec(spec)
+        spec.loader.exec_module(module)
 
 
 def generate_root_task(task_class, *args, **kwargs) -> DependencyLoggerBaseTask:
@@ -178,7 +179,7 @@ def _configure_logging(
         use_job_specific_log_file: bool) -> Iterator[Dict[str, str]]:
     with get_luigi_log_config(log_file_target=log_file_path,
                               log_level=log_level,
-                              use_job_specific_log_file=use_job_specific_log_file) as luigi_config: # type: Path
+                              use_job_specific_log_file=use_job_specific_log_file) as luigi_config:
         no_configure_logging, run_kwargs = _configure_logging_parameter(
             log_level=log_level,
             luigi_config=luigi_config,