add lookup method to fool type checker

Author: varun-r-mallya

pythonbpf/maps.py

@@ -5,4 +5,10 @@ def __init__(self, key_type, value_type, max_entries):
         self.max_entries = max_entries
         self.entries = {}
 
+    def lookup(self, key):
+        if key in self.entries:
+            return self.entries[key]
+        else:
+            return None
+
     # add other supported map functions here