what `?` means before some object attribute? and why my ts file doesn´t accept it?

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Why RPM doesn't accept my shared object as dependency?

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Why applescript doesn't accept file object in localized string command?

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Why doesn't my script accept characters?

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Why is my string doesn't accept null?

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Why won't redshift accept my fixedwidth text file

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Why won't redshift accept my fixedwidth text file

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Why Haskell doesn't accept my combinatoric "zip" definition?

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Why doesn't add method accept my inputs?

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LISP: Why doesn't mapcan accept my list give as parameters?

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Why doesn't my code accept whitespace in getline(cin, *userInput)?

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Why doesn't add method accept my inputs?

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Why doesn't my Python code accept %z as a DateTime directive?

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Why does itunecconnect not accept my geoJSON file?

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Why doesn't QComboBox.findData() accept an object as input?

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Why Calendar.before() and Calendar.after() accept object value?

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stl() decomposition won't accept univariate ts object?

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Why won't std::shared_ptr accept my deleter function object?

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Input file's accept attribute was not working for .pdf why?

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Why doesn't my .desktop file work?

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CSS content attribute, what it means

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When I cat a pid file I get a %,why and what that means?

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Why does my file input only accept one file?

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Why doesn't Android Studio recognise androidplot attribute in my xml?

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What does "+" means in HTTP Accept header?

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Why doesn't my :before class transition at all? Polymer

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perform client side validation on file input - accept attribute doesn't work

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What does public<T> void run (T object ) { } means?

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Why won't my Ubuntu GNOME accept my google password?

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Why won't my Ubuntu GNOME accept my google password?