doing string split with 2 or more split characters

[Pedroski55]

Can't see a one-liner to do this.

# add a unwanted character at the end of the string or you won't get the last wanted characters
mystring = 'ab|cd!ef|gh!ij|kl!mn|'
# define what you want to keep
wanted = 'abcdefghijklmnopqrstuvwxyz'
count = 0
for i in range(len(mystring)):    
    if not mystring[i] in wanted:
        seq = mystring[count:i]
        print(seq)
        count = i+1