AttributeError: 'NoneType' object has no attribute 'group'

[atav32]

Stracktrace

atav32@home:~/code/vimrc-to-json> python3 vimrc-to-json.py
Traceback (most recent call last):
  File "vimrc-to-json.py", line 78, in <module>
    new_file += mapToJSONList(item["after"], command)
  File "vimrc-to-json.py", line 45, in mapToJSONList
    map_json += '"' + re.match("(:\w+)", mapstring).group(1) + '"]'
AttributeError: 'NoneType' object has no attribute 'group'

.vimrc

nnoremap v     <C-V>
nnoremap <C-V> v
vnoremap v     <C-V>
vnoremap <C-V> v
noremap <Up>    <NOP>
noremap <Down>  <NOP>
noremap <Left>  <NOP>
noremap <Right> <NOP>
noremap <S-k> <NOP>
map Y y$"
vnoremap < <gv
vnoremap > >gv
noremap gk <C-u>
noremap gj <C-d>
map <C-e> <C-w>
nnoremap gs :w<Enter>
nnoremap gss :wq<Enter>
nnoremap gsss :w !sudo tee % >/dev/null<Enter>
nnoremap gq  :q<Enter>
nnoremap gqq :q!<Enter>
nnoremap gqa :qa<Enter>
nnoremap <silent> ss :split  .<Enter>
nnoremap <silent> vv :vsplit .<Enter>
nnoremap <silent> vs <C-w>t<C-w>K
nnoremap <silent> sv <C-w>t<C-w>H
nnoremap ++ 10<C-w>+
nnoremap -- 10<C-w>-
nnoremap << 5<C-w><
nnoremap >> 5<C-w>>
nnoremap gx :Explore<Enter>
nnoremap gb :b#<Enter>
noremap Q <NOP>
nmap gz za
nnoremap <Enter> zz
nnoremap gcl :g/console.log/d<Enter>
nnoremap g> ^i//<C-c>j
nnoremap g< ^:%s/\/\///c<Enter>y
nmap <F6> :set invnumber<CR>
nmap <Leader>/ :Ack<Space>
noremap <silent><esc> <esc>:noh<CR><esc>
nmap ?? :%s/<C-r><C-w>//g<Left><Left>
vmap ?? :s/<C-r><C-w>//g<Left><Left>
nmap ??? :windo %s/<C-r><C-w>//g<Left><Left>
nmap \\ :Tags <C-r><C-w>
vmap \\ :Tags <C-r><C-w>
map <silent> <leader>V :source ~/.vimrc<CR>:filetype detect<CR>:exe ":echo 'vimrc reloaded'"<CR>
nnoremap <C-e>g :tab sball<CR>
nnoremap <C-e>t :tab split<CR>
nnoremap <C-e>q :tabclose<CR>
nnoremap <C-e>h :tabp<CR>
nnoremap <C-e>j :tabp<CR>
nnoremap <C-e>k :tabn<CR>
nnoremap <C-e>l :tabn<CR>
nnoremap / /\v
vnoremap / /\v"
nnoremap <tab> %
vnoremap <tab> %
nnoremap <leader>, <c-^>
nnoremap gb :ls<CR>:b<Space>