Regex: Remove all match plus one char before all

[nilamo]

I'm late to the party, and mine looks a lot like a few of the others, but here's my entry:

orig = 'it |BS||BS||BS|this is one|BS||BS||BS|an example'

import re
regex = re.compile(r".?\|BS\|")

text = orig
replacements = 1
while replacements:
   text, replacements = regex.subn("", text, 1)
print(text) # this is an example