Format main.py using black

[diivm]

• part of Add a standard code formatter  #7
• used default config

[kunaltyagi]

I don't have a preferential config for formatting. Default should be good 'nuff

If there are no objections, I'll go ahead with the merge

[diivm]

Relevant options:

  -c, --code TEXT                 Format the code passed in as a string.
  -l, --line-length INTEGER       How many characters per line to allow.
                                  [default: 88]

  -t, --target-version [py27|py33|py34|py35|py36|py37|py38]
                                  Python versions that should be supported by
                                  Black's output. [default: per-file auto-
                                  detection]

  --py36                          Allow using Python 3.6-only syntax on all
                                  input files.  This will put trailing commas
                                  in function signatures and calls also after
                                  *args and **kwargs. Deprecated; use
                                  --target-version instead. [default: per-file
                                  auto-detection]

  --pyi                           Format all input files like typing stubs
                                  regardless of file extension (useful when
                                  piping source on standard input).

  -S, --skip-string-normalization
                                  Don't normalize string quotes or prefixes.

  --fast / --safe                 If --fast given, skip temporary sanity
                                  checks. [default: --safe]

[diivm]

@kunaltyagi
Let's get this one going!