diff --git a/pythonbpf/structs/struct_type.py b/pythonbpf/structs/struct_type.py
index 129066f..5e1698b 100644
--- a/pythonbpf/structs/struct_type.py
+++ b/pythonbpf/structs/struct_type.py
@@ -8,7 +8,7 @@ class StructType:
         self.size = size
 
     def field_idx(self, field_name):
-        return self.fields.keys().index(field_name)
+        return list(self.fields.keys()).index(field_name)
 
     def field_type(self, field_name):
         return self.fields[field_name]
diff --git a/pythonbpf/structs/structs_pass.py b/pythonbpf/structs/structs_pass.py
index 6557e68..cccc119 100644
--- a/pythonbpf/structs/structs_pass.py
+++ b/pythonbpf/structs/structs_pass.py
@@ -2,6 +2,7 @@ import ast
 import logging
 from llvmlite import ir
 from .type_deducer import ctypes_to_ir
+from .struct_type import StructType
 
 logger = logging.getLogger(__name__)
 
@@ -35,14 +36,11 @@ def process_bpf_struct(cls_node, module):
     """ Process a single BPF struct definition """
 
     fields = parse_struct_fields(cls_node)
-    total_size = calc_struct_size(fields.values())
-    struct_type = ir.LiteralStructType(fields.values())
+    field_types = list(fields.values())
+    total_size = calc_struct_size(field_types)
+    struct_type = ir.LiteralStructType(field_types)
     logger.info(f"Created struct {cls_node.name} with fields {fields.keys()}")
-    return {
-        "type": struct_type,
-        "fields": fields,
-        "size": total_size,
-    }
+    return StructType(struct_type, fields, total_size)
 
 
 def parse_struct_fields(cls_node):