<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def symbol(name: str=None, symbol_type: Type[Symbol]=Symbol) -> 'SymbolWildcard': """Create a `SymbolWildcard` that matches a single `Symbol` argument. Args: name: Optional variable name for the wildcard. symbol_type: An optional subclass of `Symbol` to further limit which kind of symbols are matched by the wildcard. Returns: A `SymbolWildcard` that matches the *symbol_type*. """

        if isinstance(name, type) and issubclass(name, Symbol) and symbol_type is Symbol:
            return SymbolWildcard(name)
        return SymbolWildcard(symbol_type, variable_name=name)