Thinkphp problems Calltoundefinedfunction

Thinkphp problems Calltoundefinedfunction reports some errors & nbsp; Calltoundefinedfunctionreplace_play_name () but I wrote this function in common. php in public functions. Also, could you tell me why ??, The function cannot be found. How can I answer thinkphp's question like this? Call to undefined function
Some errors are reported.

Call to undefined function replace_play_name ()

But I wrote this function in common. php in public functions.

Also, could you tell me why ??

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The function cannot be found.

How can I answer this question.
------ Solution --------------------
You must delete the cache after changing common. php. Is Runtime