It appears you cannot just import ctypes.windll, you need to import ctypes and then use ctypes.windll. I discovered that by printing all properties of ctypes:

import ctypes
print dir(ctypes)

What's also interesting is that IPython autocompletion was misleading here, because it didn't show windll as a possible choice when TAB-autocompleting after import ctypes..

It seems like you're trying to use a Windows module on a non Windows enviroment, if you check the ctype module it has some conditional classes:

if _os.name == "nt":

    class WinDLL(CDLL):
        """This class represents a dll exporting functions using the
        Windows stdcall calling convention.
   [...]

https://docs.python.org/3/library/ctypes.html

Aws lambda will throw you an error if you don't have the correct version of dependencies packaged with your code, which may depend on the OS (lambda runs on linux) and the python version.

Based on your requirements, it's pandas throwing you the error. To run pandas on lambda, you need to include the following packages:

pandas - code compiled for the linux, which is what lambda runs you. You can find it here https://pypi.org/project/pandas/#files download the 'manylinux' version of the .whl file, that matches your python lambda version.

• e.g. if you are running py3.7, then get pandas-0.25.3-cp37-cp37m-manylinux1_x86_64.whl

• Unzip the contents of the .whl file into the root folder of your lambda folder. This is the library version that lambda needs

• Note for pandas 0.25+, you also need to include the pytz package as well, see note below on requests

numpy - You can now get in lambda (tested for py3.7) through installing a 'layer' through the lambda console, see screenshots below.

• Doesn't seem there's a layer for py3.8 yet so you'll need to do download the correct .whl file from pypi, just like pandas https://pypi.org/project/numpy/#files

Side note on requests

• Notice that the package here https://pypi.org/project/requests/#files only have a 'none-any' version, that means the source doesn't need to be compiled, so you can safely include the version you got from pip

• this applies to the pytz dependency of pandas as well

Screenshots installing layers in aws console