load a VOTable -already accessible on the python side- into the widget
            Args:
                table: votable object

def add_table(self, table):
        """ load a VOTable -already accessible on the python side- into the widget
            Args:
                table: votable object"""

        # theses library must be installed, and are used in votable operations
        # http://www.astropy.org/
        import astropy
        
        table_array = table.__array__()
        self.table_keys= table.keys()
        table_columns= []
        for i in range(0,len(table.columns[0])):
            row_data = []

            # this step is needed in order to properly retrieve strings data
            # (otherwise, Aladin Lite shows these values as DataView object)
            for item in table_array[i]:
                if isinstance(item, bytes):
                    row_data.append(item.decode('utf-8'))
                else:
                    row_data.append(item)
            table_columns.append(row_data)

        self.table_columns = table_columns
        self.table_flag= not self.table_flag