def repo_mount_validator():
def validator(document):<EOL><INDENT>if '<STR_LIT>' in document and '<STR_LIT>' in document:<EOL><INDENT>return<EOL><DEDENT>elif '<STR_LIT>' not in document and '<STR_LIT>' not in document:<EOL><INDENT>return<EOL><DEDENT>return '<STR_LIT>'<EOL><DEDENT>return validator<EOL>
If either repo or mount are provided, they must both be provided.