add File class

csst_common/__init__.py

@@ -14,5 +14,6 @@ from .pipeline import Pipeline
 from .ccds import CCDS
 from .dfs import DFS
 from .decorator import parameterized_module_decorator
+from .file import File
 
 __version__ = "0.0.2"

csst_common/file.py

+import os
+
+
+class File:
+    def __init__(self, file_path: str = "/path/to/file.fits"):
+        self.file_path = file_path
+        self.file_path_prefix, self.file_path_ext = os.path.splitext(file_path)
+
+    def switch_extension(self, ext="wht.fits") -> str:
+        if ext.startswith("."):
+            return self.file_path_prefix + ext
+        else:
+            return self.file_path_prefix + "_" + ext