fix: add formatter modules

src/formatters/base.py

@@ -3,10 +3,9 @@ from typing import Any
 
 
 class BaseFormatter(ABC):
-    """Base formatter interface."""
+    """Base class for formatters."""
 
-    @staticmethod
     @abstractmethod
-    def format(data: Any) -> str:
+    def format(self, data: Any) -> str:
         """Format data to string."""
         pass