diff --git a/datamimic_ce/clients/database_client.py b/datamimic_ce/clients/database_client.py
index 7bad57a..ed8cea2 100644
--- a/datamimic_ce/clients/database_client.py
+++ b/datamimic_ce/clients/database_client.py
@@ -31,7 +31,7 @@ def get_by_page_with_type(self, table_name: str, pagination: DataSourcePaginatio
         """
 
     @abstractmethod
-    def get_cyclic_data(self, query: str, cyclic: bool, data_len: int, pagination: DataSourcePagination) -> list:
+    def get_cyclic_data(self, query: str, cyclic: bool, data_len: int, pagination: DataSourcePagination | None) -> list:
         """
         Get cyclic data from database
         """
diff --git a/datamimic_ce/contexts/setup_context.py b/datamimic_ce/contexts/setup_context.py
index 0c0ca75..1a4429b 100644
--- a/datamimic_ce/contexts/setup_context.py
+++ b/datamimic_ce/contexts/setup_context.py
@@ -67,8 +67,8 @@ def __init__(
         self._max_count = 1000
         self._validate = False
         self._default_error_handler = None
-        self._default_separator = default_separator
-        self._default_locale = default_locale
+        self._default_separator = default_separator or ","
+        self._default_locale: str = default_locale or "en_US"
         self._default_dataset = default_dataset
         self._default_null = None
         self._default_script = "py"
diff --git a/datamimic_ce/tasks/key_task.py b/datamimic_ce/tasks/key_task.py
index 3bd762a..609cc2f 100644
--- a/datamimic_ce/tasks/key_task.py
+++ b/datamimic_ce/tasks/key_task.py
@@ -81,7 +81,7 @@ def execute(self, ctx: Context) -> None:
             if hasattr(self._statement, "sub_statements"):
                 for stmt in self._statement.sub_statements:
                     task = task_util_cls.get_task_by_statement(root_ctx, stmt)
-                    if isinstance(task, ElementTask):
+                    if isinstance(task, ElementTask) and isinstance(ctx, GenIterContext):
                         attributes.update(task.generate_xml_attribute(ctx))
                     else:
                         raise ValueError(
diff --git a/datamimic_ce/tasks/key_variable_task.py b/datamimic_ce/tasks/key_variable_task.py
index e749937..5188c51 100644
--- a/datamimic_ce/tasks/key_variable_task.py
+++ b/datamimic_ce/tasks/key_variable_task.py
@@ -51,7 +51,7 @@ def __init__(
 
         self._element_tag = "key" if isinstance(statement, KeyStatement) else "variable"
         self._statement = statement
-        self._generator = None
+        self._generator: WeightedDataSource | None = None
         self._pagination = pagination
         self._converter_list = TaskUtil.create_converter_list(ctx, statement.converter)
 
@@ -112,8 +112,9 @@ def _determine_generation_mode(self, ctx: SetupContext):
             if not source.endswith("wgt.csv"):
                 raise ValueError(f"Data source of attribute '{self._statement.name}' must be type of: 'wgt.csv'")
             separator = self._statement.separator or ctx.default_separator
-            # TODO: mypy issue[assignment]
-            self._generator = WeightedDataSource(file_path=ctx.descriptor_dir / source, separator=separator)
+            self._generator: WeightedDataSource = WeightedDataSource(
+                file_path=ctx.descriptor_dir / source, separator=separator
+            )
             self._mode = self._GENERATOR_MODE
         elif self._statement.pattern is not None:
             self._mode = self._PATTERN_MODE
@@ -142,8 +143,8 @@ def _generate_value(self, ctx: Context):
 
         if self._mode == self._SCRIPT_MODE:
             try:
-                # TODO: mypy issue `self._statement.script` maybe None
-                value = ctx.evaluate_python_expression(self._statement.script)
+                if self._statement.script is not None:
+                    value = ctx.evaluate_python_expression(self._statement.script)
             except Exception as e:
                 if self._statement.default_value is not None:
                     value = (
@@ -174,7 +175,7 @@ def _generate_value(self, ctx: Context):
             # TODO: mypy issue: `self.statement.string` maybe None
             value = TaskUtil.evaluate_variable_concat_prefix_suffix(
                 context=ctx,
-                expr=self.statement.string,
+                expr=self.statement.string or "",
                 prefix=self._prefix,
                 suffix=self._suffix,
             )
diff --git a/datamimic_ce/tasks/variable_task.py b/datamimic_ce/tasks/variable_task.py
index 8881105..59f835d 100644
--- a/datamimic_ce/tasks/variable_task.py
+++ b/datamimic_ce/tasks/variable_task.py
@@ -130,10 +130,9 @@ def __init__(
                             len_data = ctx.data_source_len.get(statement.full_name)
                             if len_data is None:
                                 len_data = client.count_query_length(selector)
-                            # TODO: mypy issue handle when cyclic is None, pagination is None
                             file_data = client.get_cyclic_data(
                                 selector,
-                                statement.cyclic,
+                                statement.cyclic or False,
                                 len_data,
                                 pagination,
                             )