the code below doesn't work as expected. Why?

Output desired: 'o' 'n' ' ' 't' 'p' 'a' 'n'

phrase="don't panic"

plist=list(phrase)

str1="on tap"

qlist=list(str1)

for item in qlist:

if item not in plist:

plist.remove(item)

print(plist)