<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def add_empty_magic_table(self, dtype, col_names=None, groups=None):
 """ Add a blank MagicDataFrame to the contribution. You can provide either a list of column names, or a list of column group names. If provided, col_names takes precedence. """

        if dtype not in self.table_names:
            print("-W- {} is not a valid MagIC table name".format(dtype))
            print("-I- Valid table names are: {}".format(", ".join(self.table_names)))
            return
        data_container = MagicDataFrame(dtype=dtype, columns=col_names, groups=groups)
        self.tables[dtype] = data_container