Superheroes are often fodder for lunchbox covers, but one school considers the do-gooders nothing more than “violent characters.”

Recently, a young girl purportedly received a letter stating that her Wonder Woman lunchbox violated a code in which the school asks that children not bring violent images into the building in any way. “We have defined ‘violent characters’ as those who solve problems using violence,” the letter reads. “Superheroes certainly fall into that category.”

While the upcoming Batman v. Superman might show some characters’ more hostile tendencies, the lunch box in question simply featured a smiling profile of Wonder Woman and a solo action shot with her lasso — a picture that seems to best symbolize the character’s strength and confidence. The letter sparked outrage on the internet, with even Wonder Woman actress Lynda Carter retweeting a story about the lunchbox. Check out images of the item below.

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Image zoom Imgur