code: def fix_symbol(self, symbol, reverse=False):
          
          if not self.symbol_mapping:
              return symbol
  
          for old, new in self.symbol_mapping:
              if reverse:
                  if symbol == new:
                      return old
              else:
                  if symbol == old:
                      return new
  
          return symbol
docs: In comes a moneywagon format symbol, and returned in the symbol converted
          to one the service can understand.