Click to run and edit this dialog:

Run in SolveIt 
from mdhtml import to_mdhtml
print(to_mdhtml('# Alpha beta {k="v"}'), end="")
<h1 k="v">Alpha beta</h1>

print(to_mdhtml("# Alpha's beta {k=\"v\"}"), end="")
<h1>Alpha's beta {k="v"}</h1>

print(to_mdhtml("# [Alpha]{.cls} the firm's charter {k=\"v\"}"), end="")
<h1 class="cls}" firm's charter {k="v">[Alpha]</h1>

after fix

from mdhtml import to_mdhtml
print(to_mdhtml('# Alpha beta {k="v"}'), end="")
<h1 k="v">Alpha beta</h1>

print(to_mdhtml("# Alpha's beta {k=\"v\"}"), end="")
<h1 k="v">Alpha's beta</h1>

print(to_mdhtml("# [Alpha]{.cls} the firm's charter {k=\"v\"}"), end="")
<h1 k="v"><span class="cls">Alpha</span> the firm's charter</h1>