def check_symbol(self, symbol, s_list=None):
        
        all_symbols = list()
        
        # Create a super-set of symbols.
        if s_list is not None:
            all_symbols = self.get_symbols_from_list(s_list)
        else:
            all_symbols = self.get_all_symbols()
        
        # Check if the symbols is present.
        if ( symbol in all_symbols ):
            return True
        else:
            return False
@summary: Returns True if given symbol is present in the s_list.
dataset/ETHPy150Open QuantSoftware/QuantSoftwareToolkit/QSTK/qstkutil/DataAccess.py/DataAccess.check_symbol