Python: CreateByteVector function in builder. (#4453)

python/flatbuffers/builder.py

@@ -421,6 +421,27 @@ class Builder(object):
 
         return self.EndVector(len(x))
 
+    def CreateByteVector(self, x):
+        """CreateString writes a byte vector."""
+
+        self.assertNotNested()
+        ## @cond FLATBUFFERS_INTERNAL
+        self.nested = True
+        ## @endcond
+
+        if not isinstance(x, compat.binary_types):
+            raise TypeError("non-byte vector passed to CreateByteVector")
+
+        self.Prep(N.UOffsetTFlags.bytewidth, len(x)*N.Uint8Flags.bytewidth)
+
+        l = UOffsetTFlags.py_type(len(x))
+        ## @cond FLATBUFFERS_INTERNAL
+        self.head = UOffsetTFlags.py_type(self.Head() - l)
+        ## @endcond
+        self.Bytes[self.Head():self.Head()+l] = x
+
+        return self.EndVector(len(x))
+
     ## @cond FLATBUFFERS_INTERNAL
     def assertNested(self):
         """