Xcode主题 - 创建文件夹时不是目录

Question

我正在尝试从https://github.com/hdoria/xcode-themes安装Xcode主题，就像他们在底部的说明一样。我正在尝试创建一个目录。但是它一直告诉我它不是一个目录。这就是我想要做的......

08:15 PM - cd 

08:20 PM - ls
Applications/ Documents/    Dropbox/      Movies/       OneDrive/     Public/
Desktop/      Downloads/    Library/      Music/        Pictures/

08:20 PM - mkdir ~/Library/Developer/Xcode/UserData/FontAndColorThemes/
mkdir: /Users/username/Library/Developer/Xcode/UserData: Not a directory

08:20 PM - mkdir -p ~/Library/Developer/Xcode/UserData/FontAndColorThemes/
mkdir: /Users/username/Library/Developer/Xcode/UserData/FontAndColorThemes/: Not a directory