diff --git a/10-seq-hacking/vector_v5.py b/10-seq-hacking/vector_v5.py
index cf327bc..5bffd04 100644
--- a/10-seq-hacking/vector_v5.py
+++ b/10-seq-hacking/vector_v5.py
@@ -201,7 +201,9 @@
 class Vector:
     typecode = 'd'
 
-    def __init__(self, components):
+    def __init__(self, components, typecode=None):
+        if typecode:
+            self.typecode = typecode
         self._components = array(self.typecode, components)
 
     def __iter__(self):
@@ -284,5 +286,5 @@ def __format__(self, fmt_spec=''):
     def frombytes(cls, octets):
         typecode = chr(octets[0])
         memv = memoryview(octets[1:]).cast(typecode)
-        return cls(memv)
+        return cls(memv, typecode)
 # END VECTOR_V5