feat(cast): add module with casting operations

src/agora/utils/cast.py

+#!/usr/bin/env jupyter
+
+"""
+Convert some types to others
+"""
+
+
+def _str_to_int(x: str or None):
+    """
+    Cast string as int if possible. If Nonetype return None.
+    """
+    if x:
+        try:
+            return int(x)
+        except:
+            return x