Returns the unique rows of a table.
input_table : Table object or a value that
will initialize a `~astropy.table.Table` object
Input table.
keys : str or list of str
Name(s) of column(s) used to unique rows. Default is to use all columns.
silent : boolean
If True masked value column(s) are silently removed from keys. If False an exception is raised when keys contains masked value column(s). Default is False.
unique_table : Table object
Table containing only the unique rays of input_table.