Maria Delsocorro Rentaría appeals the district court’s judgment revoking her su *218 pervised release and imposing a sentence of four months to be followed by a 24-month term of supervised release. Although Rentaría has been released from prison, her appeal is not moot because it is possible that the district court will alter her remaining term of supervised release if it is determined that she served excess prison time as a result of the district court’s error. See Johnson v. Pettiford, 442 F.3d 917, 918 (5th Cir. 2006).

Rentaría contends that the district court erred in failing to apply the exception to mandatory revocation under 18 U.S.C. § 3583(d) based on her failure to pass drug tests on two occasions. She asserts that the district court committed a significant procedural error by relying on a factor that Congress intended to exclude from consideration under § 3583(d).

This court reviews the district court’s statutory interpretation de novo. United States v. Courtney, 979 F.2d 45, 48 (5th Cir. 1992). Pursuant to § 3583(g), revocation of supervised release is mandatory if, inter alia, the defendant possesses a controlled substance or tests positive for drug use more than three times in one year. However, § 3583(d) provides an exception to mandatory revocation under § 3583(g), requiring the district court to consider “the availability of appropriate substance abuse treatment programs, or an individual’s current or past participation in such programs, ... when considering any action against a defendant who fails a drug test.” § 3583(d).

Rentaría was subject to mandatory revocation because she admitted using marijuana on two occasions, thus implicitly admitting the possession thereof. United States v. Smith, 978 F.2d 181, 182 (5th Cir. 1992). The district court’s comments reflect that it was aware of the exception to imposing a term of imprisonment upon mandatory revocation but its statements also showed that, based on Rentaria’s conduct, the application of the exception was not warranted. Contrary to Rentaria’s arguments, the district court considered factors other than Rentaria’s mere failure to pass two' drug tests.

Moreover, the district court stated that, in light of the record before it, it would have revoked Rentaria’s supervised release whether or not revocation was mandatory. Thus, any error regarding the nature of the revocation was harmless. See United States v. Martinez-Romero, 817 F.3d 917, 924-25 (5th Cir. 2016).

The judgment is AFFIRMED.