Address @feluelle's comments

sql-cli/sql_cli/workflow_directory_parser.py

@@ -2,11 +2,13 @@
 
 from abc import abstractmethod
 from pathlib import Path
-from typing import Any, Iterable
+from typing import Iterable
 
 import airflow
 import frontmatter
 import yaml
+from airflow.models import BaseOperator
+from yaml.scanner import ScannerError
 
 from astro.sql import LoadFileOperator
 from astro.sql.operators.transform import TransformOperator
@@ -147,7 +149,7 @@ def write_raw_content_to_target_path(self) -> None:
         target_path.write_text(self.raw_content)
 
     @abstractmethod
-    def to_operator(self) -> Any:
+    def to_operator(self) -> BaseOperator:
         raise NotImplementedError()
 
 
@@ -185,12 +187,18 @@ class YamlFile(WorkflowFile):
 
     def __init__(self, root_directory: Path, path: Path, target_directory: Path) -> None:
         super().__init__(root_directory, path, target_directory, YAML_FILE_TYPE)
-        with open(path) as yaml_file:
-            self.yaml_content = yaml.load(yaml_file, Loader=yaml.Loader)
+        with path.open() as yaml_file:
+            self.yaml_content = yaml.safe_load(yaml_file)
         self.operator = self._get_operator()
         self.yaml_file_name = self.path.stem
 
     def _get_operator(self) -> str:
+        top_level_keys = list(self.yaml_content.keys())
+        top_level_keys_count = len(top_level_keys)
+        if top_level_keys_count > 1:
+            raise ScannerError(
+                f"Only one top level operator expected. Got {top_level_keys_count} operators: {top_level_keys}"
+            )
         operator = list(self.yaml_content.keys())[0]
         if operator not in YamlFile.operator_instance_builder_callable_map:
             raise NotImplementedError(f"Operator support for {operator} not available")
@@ -205,7 +213,7 @@ def to_operator(self) -> LoadFileOperator:
         )
 
 
-FILE_TYPE_CLASS_MAP = {SQL_FILE_TYPE: SqlFile, YAML_FILE_TYPE: YamlFile}
+SUPPORTED_FILES = {"*.sql": SqlFile, "*.yaml": YamlFile, "*.yml": YamlFile}
 
 
 def get_files_by_type(
@@ -221,15 +229,17 @@ def get_files_by_type(
     :returns: the workflow files found in the directory.
     """
     return {
-        FILE_TYPE_CLASS_MAP[file_type](
+        SUPPORTED_FILES[file_type](
             root_directory=directory, path=child, target_directory=target_directory  # type: ignore
         )
-        for child in directory.rglob(f"*.{file_type}")
+        for child in directory.rglob(file_type)
         if child.is_file() and not child.is_symlink()
     }
 
 
 def get_workflow_files(directory: Path, target_directory: Path | None) -> set[WorkflowFile]:
-    sql_files = get_files_by_type(directory, SQL_FILE_TYPE, target_directory=target_directory)
-    yaml_files = get_files_by_type(directory, YAML_FILE_TYPE, target_directory=target_directory)
-    return sql_files.union(yaml_files)
+    workflow_files: set[WorkflowFile] = set()
+    for file_type in SUPPORTED_FILES:
+        files = get_files_by_type(directory, file_type, target_directory=target_directory)
+        workflow_files = workflow_files.union(files)
+    return workflow_files