@property<EOL><INDENT>def opaque_sky_cover(self):<DEDENT>
return self._get_data_by_field(<NUM_LIT>)<EOL>
Return annual Opaque Sky Cover as a Ladybug Data Collection.

        This is the value for opaque sky cover (tenths of coverage). (i.e. 1 is 1/10
        covered. 10 is total coverage). (Amount of sky dome in tenths covered by
        clouds or obscuring phenomena that prevent observing the sky or higher cloud
        layers at the time indicated.) This is not used unless the field for Horizontal
        Infrared Radiation Intensity is missing and then it is used to calculate
        Horizontal Infrared Radiation Intensity. Minimum value is 0; maximum value is
        10; missing value is 99.

        Read more at: https://energyplus.net/sites/all/modules/custom/nrel_custom/pdfs
            /pdfs_v8.4.0/AuxiliaryPrograms.pdf (Chapter 2.9.1)