I'm developing a chatbot using heroku and python. I have a file fetchWelcome.py in which I have written a function. I need to import the function from fetchWelcome into my main file. 
I wrote "from fetchWelcome import fetchWelcome" in main file. But because we need to mention all the dependencies in the requirement file, it shows error. I don't know how to mention user defined requirement.
How can I import the function from another file into the main file ? Both the files ( main.py and fetchWelcome.py ) are in the same folder.
If we need to import function from fileName into main.py, write "from .fileName import functionName". Thus we don't need to write any dependency in requirement file.
Heroku Python import local functions