proc `+`(p: GgPlot; d: VegaTeX) {....raises: [ValueError, Exception, KeyError,
    FormulaMismatchError, AestheticError, TimeFormatParseError, TimeParseError,
    OSError, IOError, PixieError, JsonParsingError], tags: [RootEffect,
    TimeEffect, WriteDirEffect, ReadDirEffect, WriteIOEffect, ReadEnvEffect,
    ReadIOEffect, ExecIOEffect].}