diff --git a/convert-lora-to-ggml.py b/convert-lora-to-ggml.py
index c6d48b976..8a2085c25 100644
--- a/convert-lora-to-ggml.py
+++ b/convert-lora-to-ggml.py
@@ -3,45 +3,11 @@ import os
 import re
 import struct
 import sys
-from dataclasses import dataclass
-from typing import Any, Sequence
+from typing import Any, Dict, Sequence, TextIO
 
-import numpy as np
 import torch
 
-
-# TODO: import this from convert.py once #545 is merged
-@dataclass(frozen=True)
-class UnquantizedDataType:
-    name: str
-
-
-DT_F16 = UnquantizedDataType("F16")
-DT_F32 = UnquantizedDataType("F32")
-
-
-@dataclass(frozen=True)
-class QuantizedDataType:
-    groupsize: int
-    have_addends: bool
-    have_g_idx: bool
-
-
-DataType = UnquantizedDataType
-
-DATA_TYPE_TO_FTYPE: dict[DataType, int] = {
-    DT_F32: 0,
-    DT_F16: 1,
-}
-
-DATA_TYPE_TO_NUMPY: dict[DataType, np.dtype[Any]] = {
-    DT_F16: np.dtype(np.float16),
-    DT_F32: np.dtype(np.float32),
-}
-
-NUMPY_TYPE_TO_DATA_TYPE: dict[np.dtype[Any], DataType] = {
-    dtype: data_type for (data_type, dtype) in DATA_TYPE_TO_NUMPY.items()
-}
+from convert import DATA_TYPE_TO_FTYPE, NUMPY_TYPE_TO_DATA_TYPE, DataType
 
 HF_SUBLAYER_TO_GGML = {
     "self_attn.q_proj": "attention.wq",
@@ -59,7 +25,7 @@ HF_SUBLAYER_TO_GGML = {
 }
 
 
-def translate_tensor_name(t):
+def translate_tensor_name(t: str) -> str:
     match = re.match(r".*layers\.(\d+)\.(\w+\.\w+)\.lora_(A|B)\.weight", t)
     if match:
         nn = match.group(1)
@@ -80,13 +46,15 @@ def translate_tensor_name(t):
         sys.exit(1)
 
 
-def write_file_header(fout, params):
+def write_file_header(fout: TextIO, params: Dict[str, Any]) -> None:
     fout.write(b"ggla"[::-1])  # magic (ggml lora)
     fout.write(struct.pack("i", 1))  # file version
     fout.write(struct.pack("ii", params["r"], params["lora_alpha"]))
 
 
-def write_tensor_header(self, name: str, shape: Sequence[int], data_type: 1) -> None:
+def write_tensor_header(
+    self, name: str, shape: Sequence[int], data_type: DataType
+) -> None:
     sname = name.encode("utf-8")
     fout.write(
         struct.pack(