The Pennsylvania Supreme Court is set to weigh in on numerous high-profile cases during an unusually lengthy oral argument session expected to begin Tuesday in Harrisburg.

A full complement of the high court is expected to spend three days hearing arguments in 17 cases, considering questions over the legality of Philadelphia's tax on sweetened beverages, the custody rights of same-sex partners, how posts on Facebook could impact discovery in a civil lawsuit, and the capital case against a man who sent Pennsylvania authorities on a lengthy manhunt after a sniper attack outside a police station that left one officer dead.

Typically, Supreme Court argument sessions last two days. However, several cases the court is set to preside over during the Harrisburg session had been set for argument during the high court's March session in Philadelphia. That session, however, had been cut short due to a snow storm.

The cases rolled into the Harrisburg session include questions about whether failing to fully cover a concrete wall in a school's gymnasium with protective matting fits the narrow exception for governmental immunity, and whether the widow of a man who drowned during the Philadelphia Triathlon can sue the event organizers, despite the decedent having signed a waiver assuming all the risks of participating in the event.

The first case the justices are set to hear focuses on the controversial sweetened beverage tax that Philadelphia put into effect at the start of 2017. The justices agreed to hear argument about whether it violates Pennsylvania's Sterling Act, which prohibits Philadelphia from imposing a tax on a transaction or subject that the state already taxes.

Last year, the Commonwealth Court gave the green light to the tax, which is the first of its kind in the nation, finding that the levy wasn't a sales tax and didn't violate the Sterling Act. The ruling rejected the arguments of several retailers and beverage distributors, as well as the American Beverage Association, that the tax wasn't simply a levy on sweetened drinks, but instead a “power grab” by the city that could undermine businesses and overlapped with the already existing state sales tax.

The second case the justices are set to hear Tuesday deals with whether the former same-sex partner of a child's biological mother can claim she is entitled to custody of the child since she has no biological connection to him, nor has she legally adopted him.

A Superior Court panel last year determined that the former partner cannot claim custody, and upheld a decision by a Centre County judge, who found that the former partner, who had been in a relationship with the biological mother of a son born in Florida through artificial insemination, was not entitled to custody of the boy because she was not legally considered a parent.

According to court papers, the biological mother alleged in preliminary objections to the custody suit that the decision to have the child was hers alone and her former partner's role was solely that of her girlfriend. The motion claimed that she made all of the important decisions regarding the child, that her former partner provided minimal financial support and that mother and son both moved out of the former partner's Florida home to Pennsylvania when the child was 6 years old. The former partner, however, countered that she had standing in loco parentis under Pennsylvania's Child Custody Law.

The first case the justices are set to hear Thursday involves Eric Frein, who faces the death penalty after being convicted of first-degree murder for a 2014 sniper ambush on the Blooming Grove state police barracks. Under state law, the Supreme Court must review all capital cases.

The last case the justices are set to consider during the three-day session is Nicolaou v. Martin. That case involves woman who aims to have her lawsuit reinstated against a doctor who allegedly misdiagnosed her Lyme disease as multiple sclerosis. The woman's case was initially tossed out partly due to Facebook posts indicating she knew she suffered from the disease years before filing suit.

Last year, a split Superior Court panel determined that Facebook posts made soon after her diagnosis indicating she suspected she had Lyme disease several years before filing suit undercut her argument that her case should have been allowed to proceed under an exception to the discovery rule. The nine-judge panel tossed the case, holding that Nancy Nicolaou failed to sue the doctor within the two-year statute of limitations.

The justices specifically agreed to hear arguments over whether the plaintiff's claims met an exception to the discovery rule since she “did not and was financially unable to, confirm [the defendant's] negligent misdiagnosis until final medical testing confirmed she had Lyme disease.”