Solar_Filter::setChainRequire()
    public
    void
     Solar_Filter::setChainRequire 
         ( string  $key
        , bool  $flag  = true
    
 )
Sets whether or not a particular data key is required to be present and non-blank in the data being processed by applyChain().
Parameters
- (string) - $key: The data key.
- (bool) - $flag: True if required, false if not. Default true.
Returns
- (void) 
Description
Sets whether or not a particular data key is required to be present and non-blank in the data being processed by applyChain().