diff --git a/pyatmos/utils/__init__.py b/pyatmos/utils/__init__.py
index e7b3ecf..a60958d 100644
--- a/pyatmos/utils/__init__.py
+++ b/pyatmos/utils/__init__.py
@@ -3,14 +3,15 @@ pyatmos utils subpackage
 
 This subpackage defines the following functions:
 
-# try_download.py
+Const.py - Defines some basic physical constants at sea level.
 
-wraplon - Wrap a longitude in range of [0,360] to [-180,180]
-
-hms2s - Convert hour/minute/second to seconds
-
-hms2h - Convert hour/minute/second to hours
-
-tqdm_request - Try to download files from a remote server by request.
+try_download.py
+    tqdm_request - Try to download files from a remote server by request with a colored progress bar.
 
+utils.py
+    vectorize - Vectorize a number(int, float) or a list to a numpy array.
+    wraplon - Wrap a longitude in range of [0,360] to [-180,180]
+    hms_conver - Convert the form of hour/minute/second to hours and seconds.
+    alt_conver - Fulfill conversions between geometric altitudes and geopotential altitudes. 
+    check_altitude - Checks if altitudes are inside a valid range.
 '''
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