diff --git a/alpharaw/utils/centroiding.py b/alpharaw/utils/centroiding.py
index f9b42f6..4d872a6 100644
--- a/alpharaw/utils/centroiding.py
+++ b/alpharaw/utils/centroiding.py
@@ -1,4 +1,4 @@
-# Modified from AlphaPept
+from typing import Tuple
 
 import numpy as np
 from numba import njit
@@ -6,10 +6,28 @@
 
 @njit
 def naive_centroid(
-    peak_mzs,
-    peak_intens,
-    centroiding_ppm=20.0,
-):
+    peak_mzs: np.ndarray,
+    peak_intensities: np.ndarray,
+    centroiding_ppm: float = 20.0,
+) -> Tuple[np.ndarray, np.ndarray]:
+    """
+    A naive centroiding algorithm.
+
+    Parameters
+    ----------
+    peak_mzs : np.ndarray
+        peak m/z values to centroid.
+    peak_intensities : np.ndarray
+        peak intensities to centroid.
+    centroiding_ppm : float, optional
+        The centroiding ppm, by default 20.0
+
+    Returns
+    -------
+    Tuple
+        ndarray: peak m/z array
+        ndarray: peak intensity array
+    """
     mz_list = []
     inten_list = []
     start, stop = 0, 1
@@ -17,18 +35,25 @@ def naive_centroid(
     while start < len(peak_mzs):
         stop = _find_sister_peaks(peak_mzs, centroiding_peak_tols, start)
         mz_list.append(
-            np.average(peak_mzs[start:stop], weights=peak_intens[start:stop])
+            np.average(peak_mzs[start:stop], weights=peak_intensities[start:stop])
         )
-        inten_list.append(np.sum(peak_intens[start:stop]))
+        inten_list.append(np.sum(peak_intensities[start:stop]))
         start = stop
     return (
         np.array(mz_list, dtype=peak_mzs.dtype),
-        np.array(inten_list, dtype=peak_intens.dtype),
+        np.array(inten_list, dtype=peak_intensities.dtype),
     )
 
 
 @njit
-def _find_sister_peaks(peak_mzs, centroiding_peak_tols, start):
+def _find_sister_peaks(
+    peak_mzs: np.ndarray, centroiding_peak_tols: np.ndarray, start: int
+):
+    """
+    Find sister peak stop idx for the given start idx.
+    Sister peaks refers to peaks from the same ion in profile mode.
+    Internal function.
+    """
     stop = start + 1
     for i in range(start + 1, len(peak_mzs)):
         if peak_mzs[i] - peak_mzs[start] <= centroiding_peak_tols[start]:
diff --git a/alpharaw/utils/ms_path_utils.py b/alpharaw/utils/ms_path_utils.py
index 6884f43..d07a3cd 100644
--- a/alpharaw/utils/ms_path_utils.py
+++ b/alpharaw/utils/ms_path_utils.py
@@ -1,6 +1,6 @@
 import os
 
-_special_ms_exts: list = [
+_SPECIAL_MS_EXTS: list = [
     ".ms_data.hdf",  # alphapept
     ".raw.hdf",  # alpharaw
     ".raw.hdf5",  # alpharaw
@@ -14,10 +14,30 @@
 ]
 
 
-def get_raw_name(ms_file: str, special_ms_exts: list = _special_ms_exts):
+def get_raw_name(ms_file: str) -> str:
+    """
+    Get `raw_name` (base name of RAW data file) from the MS file path
+    by removing the extensions defined in :data:`_SPECIAL_MS_EXTS`.
+
+    Parameters
+    ----------
+    ms_file : str
+        The absolute or relative path of the RAW file.
+
+    Returns
+    -------
+    str
+        The `raw_name` without extension.
+
+    Examples
+    --------
+    >>> get_raw_name("/MS/files/your_raw_name.raw")
+    'your_raw_name'
+
+    """
     raw_name = os.path.basename(ms_file)
     lower_name = raw_name.lower()
-    for _ext in special_ms_exts:
+    for _ext in _SPECIAL_MS_EXTS:
         if lower_name.endswith(_ext.lower()):
             raw_name = raw_name[: -len(_ext)]
             break
@@ -27,7 +47,7 @@ def get_raw_name(ms_file: str, special_ms_exts: list = _special_ms_exts):
 
 
 def parse_ms_files_to_dict(
-    ms_file_list: list, special_ms_exts: list = _special_ms_exts
+    ms_file_list: list,
 ) -> dict:
     """
     Parse spectrum file paths into a dict:
@@ -49,6 +69,6 @@ def parse_ms_files_to_dict(
 
     ms_file_dict = {}
     for ms_file in ms_file_list:
-        raw_name = get_raw_name(ms_file, special_ms_exts)
+        raw_name = get_raw_name(ms_file, _SPECIAL_MS_EXTS)
         ms_file_dict[raw_name] = ms_file
     return ms_file_dict