== Why is this an issue?

include::../description.adoc[]

=== Noncompliant code example

[source,python]
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r"(?:)*"      # same as the empty regex, the '*' accomplishes nothing
r"(?:|x)*"    # same as the empty regex, the alternative has no effect
r"(?:x|)*"    # same as 'x*', the empty alternative has no effect
r"(?:x*|y*)*" # same as 'x*', the first alternative would always match, y* is never tried
r"(?:x?)*"    # same as 'x*'
r"(?:x?)+"    # same as 'x*'
----


=== Compliant solution

[source,python]
----
r"x*"
----