If the tree name isn't specified, uproot.open() is used to find the first tree in the file. However, if the filename has a colon in it, this operation will fail, since uproot tries to interpret whatever follows the colon as a key in the file. We need to use uproot.open({filename: None}) to avoid this. See also https://github.com/CoffeaTeam/coffea/pull/771.
If the tree name isn't specified,
uproot.open()is used to find the first tree in the file. However, if the filename has a colon in it, this operation will fail, sinceuproottries to interpret whatever follows the colon as a key in the file. We need to useuproot.open({filename: None})to avoid this. See also https://github.com/CoffeaTeam/coffea/pull/771.