diff --git a/baseInterface.go b/baseInterface.go
index 13eceb3..07466fc 100644
--- a/baseInterface.go
+++ b/baseInterface.go
@@ -13,6 +13,7 @@ type BaseApChain interface {
 }
 
 // Func used to add parsers for other attributes not yet included in the library
+// It is expected that, on success, the function removes its key from the raw map
 type UnmarshalFunc func(map[string]any, BaseApChain) (BaseApChain, error)
 
 // The minimum data every AP object has
@@ -39,7 +40,7 @@ func UnmarshalBaseObject(raw map[string]any, _ BaseApChain) (BaseApChain, error)
 	}
 	id, ok := rawId.(string)
 	if !ok {
-		return nil, BadFieldValueError{KEY_ID, rawId, ""}
+		return nil, BadFieldValueError[string]{KEY_ID, rawId, ""}
 	}
 
 	rawObjType, ok := raw[KEY_TYPE]
@@ -48,7 +49,7 @@ func UnmarshalBaseObject(raw map[string]any, _ BaseApChain) (BaseApChain, error)
 	}
 	objType, ok := rawObjType.([]string)
 	if !ok {
-		return nil, BadFieldValueError{KEY_TYPE, rawObjType, []string{}}
+		return nil, BadFieldValueError[[]string]{KEY_TYPE, rawObjType, []string{}}
 	}
 
 	return &BaseObject{