Disable emacs from converting tabs to spaces - emacs

Question

I've recently started using Emacs and an issue I've been facing is that the editor automatically converts all the tabs to spaces. It has started to get a bit annoying now.
Here's my .emacs file for reference:
(require 'package)
(let* ((no-ssl (and (memq system-type '(windows-nt ms-dos))
(not (gnutls-available-p))))
(proto (if no-ssl "http" "https")))
(when no-ssl
(warn "\
Your version of Emacs does not support SSL connections,
which is unsafe because it allows man-in-the-middle attacks.
There are two things you can do about this warning:
1. Install an Emacs version that does support SSL and be safe.
2. Remove this warning from your init file so you won't see it again."))
;; Comment/uncomment these two lines to enable/disable MELPA and MELPA Stable as desired
(add-to-list 'package-archives (cons "melpa" (concat proto "://melpa.org/packages/")) t)
;;(add-to-list 'package-archives (cons "melpa-stable" (concat proto "://stable.melpa.org/packages/")) t)
(when (< emacs-major-version 24)
(add-to-list 'package-archives (cons "gnu" (concat proto "://elpa.gnu.org/packages/")))))
(package-initialize)
(custom-set-variables
'(custom-enabled-themes (quote (dracula)))
'(custom-safe-themes)
'(display-line-numbers-type (quote relative))
'(global-display-line-numbers-mode t)
'(menu-bar-mode nil)
'(package-selected-packages
(quote
(company-irony-c-headers company-irony micgoline elpy company-jedi molokai-theme gruvbox-theme autopair auto-complete anaconda-mode nyan-mode dracula-theme company)))
'(scroll-bar-mode nil)
'(tool-bar-mode nil))
(custom-set-faces
)
(setq make-backup-files nil)
(setq auto-save-default nil)
(setq inhibit-startup-message t) ;; hide the startup message
(elpy-enable)
(pyenv-mode)
(setq python-shell-interpreter "ipython"
python-shell-interpreter-args "-i --simple-prompt")
(require 'powerline)
Any suggestions on how to stop emacs from doing this behaviour?

Answer 1

As suggested by Drew, I am posting this as answer:
Did you check variable indent-tabs-mode?
With this you should be able to switch between emacs using spaces or tabs.
As described in the emacs wiki here I would assume, some active mode is setting this to nil in your emacs.
You can find another explanation with links to discussions about if tabs are evil or not here
EDIT:
It seems that strangely the python-mode sets indent-tabs-mode to t.
Maybe this Emacs Wiki entry solves your problem. This snippet from the wiki:
(add-hook 'python-mode-hook
(lambda ()
(setq-default indent-tabs-mode t)
(setq-default tab-width 4)
(setq-default py-indent-tabs-mode t)
(add-to-list 'write-file-functions 'delete-trailing-whitespace)))
looks like it will do the trick.
Hope this helps.