After struggling, both critically and commercially, with the earliest installments of its so-called DC Extended Universe, Warner Bros. appeared to veer away from the franchise's signature dark tone with Wonder Woman, Aquaman and the upcoming Shazam! It, therefore, was a bit of a surprise last year when Margot Robbie described the planned Harley Quinn spinoff as "an R-rated girl gang film." That project, of course, became Birds of Prey (And The Fantabulous Emancipation of One Harley Quinn), which certainly appears to be following through on that vision.

Although the studio insists there's "NO confirmed rating" for the Suicide Squad spinoff, the cast teaser released on Monday certainly suggests that Birds of Prey is aiming for R.

The clue comes in the form of Cassandra Cain's brightly colored cast, decorated with symbols representing members of the Birds of Prey -- an arrow or crossbow bolt for Huntress, playing cards for Harley, etc. -- and lots of profanity: "asshole," "bitch," "shit hole" and, most notably, "fuck." It's the F-bomb that would seem the clearest indication the film is headed toward R territory, because of the classification and ratings rules of the Motion Picture Association of America.

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According to the Hollywood trade association, "A motion picture’s single use of one of the harsher sexually-derived words, though only as an expletive, initially requires at least a PG-13 rating. More than one such expletive requires an R-rating, as must even one of those words used in a sexual context."

It's only one F-bomb, so far, and movies have gotten away with two and still managed to remain PG-13 (Beetlejuice, for instance), but we have to consider how many times Cassandra's cast will be seen on screen, and whether any of the characters are likely to vocalize what's scrawled upon it.

We know Cassandra's cast could very well be changed before the the final edit, but there's a fair chance the F-bomb will appear, throughout Birds of Prey. The movie is believed to center on Harley rounding up a squad to save Cassandra, a troubled teen, placing them in the cross hairs of villains like Black Mask and Victor Zsasz, who often dabble in drugs, weapons and human trafficking. It's unlikely the vigilantes -- Harley, Black Canary, Huntress and Renee Montoya -- will watch their language while taking on such depraved foes.

An image of Mary Elizabeth Winstead as Huntress from Birds of Prey.

The MPAA guidelines also stipulate that, "The Rating Board nevertheless may rate such a motion picture PG-13 if, based on a special vote by a two-thirds majority, the Raters feel that most American parents would believe that a PG-13 rating is appropriate because of the context or manner in which the words are used or because the use of those words in the motion picture is inconspicuous."

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That means expletives on a wall or a cast may not necessarily demand an R rating, but nothing that we've seen thus far of Birds of Prey (And The Fantabulous Emancipation of One Harley Quinn) seems "inconspicuous."

Directed by Cathy Yan from a script by Christina Hodson, Birds of Prey (And The Fantabulous Emancipation of One Harley Quinn) stars Margot Robbie, Jurnee Smollett-Bell, Mary Elizabeth Winstead, Rosie Perez, Ewan McGregor, Steven Williams, Derek Wilson, Dana Lee, Francois Chau, Chris Messina and Matthew Willig. It is scheduled to be released on Feb. 7, 2020.