我该如何解决此警告?

警告是"未声明的选择器'forwardGeocoderDidFail:withErrorMessage:'".为什么我会收到此警告,如何解决?
这是我的代码:
if (!handeledByBlocks && self.delegate) {
if (!parseError && parser.statusCode == G_GEO_SUCCESS)
{
[self.delegate forwardGeocodingDidSucceed:self withResults:parser.results];
}
else if ([self.delegate respondsToSelector:@selector(forwardGeocoderDidFail:withErrorMessage:)])
{
[self.delegate forwardGeocodingDidFail:self withErrorCode:parser.statusCode andErrorMessage:[parseError localizedDescription]];
}
}
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