You can create a temporary archive to get rid of the password :
import zipfile
import StringIO
path = "dev.zip"
encrypted_zip = zipfile.ZipFile( path )
encrypted_zip.setpassword("pass")
print encrypted_zip.namelist()
with zipfile.ZipFile('spam.zip', 'w') as myzip:
for nested_file in encrypted_zip.namelist():
myzip.write(encrypted_zip.read(nested_file))
The script copy files for the password-protected archive 'dev.zip' into the uncrypted archive 'spam.zip'. ( do not forget to destroy the archive after).