add optional checks for invalid handles.
add optional checks for invalid handles.

iAMr00t/opencog,zhaozengguang/opencog,misgeatgit/atomspace,andre-senna/opencog,rTreutlein/atomspace,rodsol/opencog,TheNameIsNigel/opencog,rTreutlein/atomspace,gavrieltal/opencog,ArvinPan/opencog,roselleebarle04/opencog,kim135797531/opencog,AmeBel/atomspace,williampma/opencog,jlegendary/opencog,ceefour/opencog,anitzkin/opencog,gavrieltal/opencog,ceefour/opencog,virneo/atomspace,jswiergo/atomspace,ruiting/opencog,sumitsourabh/opencog,kinoc/opencog,shujingke/opencog,zhaozengguang/opencog,rohit12/opencog,ceefour/atomspace,misgeatgit/atomspace,anitzkin/opencog,Tiggels/opencog,cosmoharrigan/atomspace,Selameab/atomspace,gaapt/opencog,ArvinPan/opencog,yantrabuddhi/opencog,gavrieltal/opencog,prateeksaxena2809/opencog,sumitsourabh/opencog,eddiemonroe/opencog,rodsol/atomspace,prateeksaxena2809/opencog,andre-senna/opencog,virneo/atomspace,ceefour/atomspace,sumitsourabh/opencog,gaapt/opencog,prateeksaxena2809/opencog,eddiemonroe/atomspace,inflector/opencog,sanuj/opencog,Allend575/opencog,eddiemonroe/opencog,roselleebarle04/opencog,eddiemonroe/opencog,ruiting/opencog,williampma/atomspace,Selameab/opencog,Tiggels/opencog,jlegendary/opencog,gaapt/opencog,iAMr00t/opencog,misgeatgit/opencog,virneo/opencog,rodsol/opencog,misgeatgit/opencog,cosmoharrigan/opencog,gaapt/opencog,Allend575/opencog,AmeBel/opencog,kinoc/opencog,AmeBel/opencog,misgeatgit/opencog,cosmoharrigan/atomspace,jlegendary/opencog,yantrabuddhi/atomspace,inflector/opencog,inflector/opencog,rTreutlein/atomspace,rohit12/atomspace,rohit12/opencog,ArvinPan/opencog,MarcosPividori/atomspace,Tiggels/opencog,Selameab/atomspace,inflector/opencog,UIKit0/atomspace,tim777z/opencog,Allend575/opencog,misgeatgit/opencog,roselleebarle04/opencog,roselleebarle04/opencog,cosmoharrigan/opencog,williampma/atomspace,sumitsourabh/opencog,printedheart/opencog,williampma/opencog,ArvinPan/atomspace,rodsol/opencog,yantrabuddhi/opencog,jswiergo/atomspace,zhaozengguang/opencog,eddiemonroe/opencog,printedheart/atomspace,sumitsourabh/opencog,iAMr00t/opencog,sanuj/opencog,anitzkin/opencog,sanuj/opencog,rohit12/atomspace,gaapt/opencog,kim135797531/opencog,kim135797531/opencog,andre-senna/opencog,jlegendary/opencog,yantrabuddhi/opencog,Selameab/opencog,prateeksaxena2809/opencog,ruiting/opencog,eddiemonroe/atomspace,AmeBel/opencog,Allend575/opencog,kinoc/opencog,yantrabuddhi/atomspace,misgeatgit/atomspace,ruiting/opencog,virneo/opencog,jswiergo/atomspace,anitzkin/opencog,tim777z/opencog,Selameab/atomspace,prateeksaxena2809/opencog,Selameab/atomspace,williampma/opencog,kinoc/opencog,eddiemonroe/opencog,shujingke/opencog,andre-senna/opencog,inflector/opencog,misgeatgit/atomspace,eddiemonroe/opencog,UIKit0/atomspace,sanuj/opencog,inflector/opencog,tim777z/opencog,roselleebarle04/opencog,printedheart/atomspace,shujingke/opencog,kinoc/opencog,TheNameIsNigel/opencog,iAMr00t/opencog,yantrabuddhi/opencog,Allend575/opencog,inflector/atomspace,cosmoharrigan/opencog,gavrieltal/opencog,sumitsourabh/opencog,misgeatgit/opencog,prateeksaxena2809/opencog,virneo/atomspace,ruiting/opencog,Selameab/opencog,rodsol/opencog,rodsol/atomspace,ruiting/opencog,kinoc/opencog,rohit12/opencog,rTreutlein/atomspace,AmeBel/atomspace,rodsol/opencog,AmeBel/atomspace,MarcosPividori/atomspace,ArvinPan/opencog,ceefour/atomspace,ArvinPan/atomspace,printedheart/opencog,virneo/opencog,yantrabuddhi/opencog,rohit12/opencog,kim135797531/opencog,williampma/atomspace,sumitsourabh/opencog,kim135797531/opencog,zhaozengguang/opencog,gavrieltal/opencog,gaapt/opencog,rohit12/atomspace,yantrabuddhi/atomspace,virneo/opencog,Tiggels/opencog,ceefour/opencog,inflector/atomspace,ArvinPan/atomspace,misgeatgit/opencog,tim777z/opencog,ArvinPan/atomspace,yantrabuddhi/atomspace,eddiemonroe/atomspace,prateeksaxena2809/opencog,shujingke/opencog,eddiemonroe/opencog,anitzkin/opencog,rodsol/atomspace,ArvinPan/opencog,sanuj/opencog,TheNameIsNigel/opencog,yantrabuddhi/atomspace,gaapt/opencog,williampma/atomspace,virneo/atomspace,ceefour/atomspace,iAMr00t/opencog,Allend575/opencog,printedheart/opencog,anitzkin/opencog,williampma/opencog,rodsol/opencog,roselleebarle04/opencog,gavrieltal/opencog,cosmoharrigan/opencog,Tiggels/opencog,TheNameIsNigel/opencog,andre-senna/opencog,andre-senna/opencog,AmeBel/opencog,ruiting/opencog,jlegendary/opencog,jswiergo/atomspace,ArvinPan/opencog,virneo/opencog,virneo/opencog,TheNameIsNigel/opencog,misgeatgit/opencog,eddiemonroe/atomspace,inflector/atomspace,inflector/opencog,MarcosPividori/atomspace,jlegendary/opencog,UIKit0/atomspace,rodsol/atomspace,anitzkin/opencog,printedheart/opencog,roselleebarle04/opencog,zhaozengguang/opencog,misgeatgit/opencog,printedheart/opencog,inflector/atomspace,printedheart/opencog,shujingke/opencog,AmeBel/opencog,tim777z/opencog,shujingke/opencog,misgeatgit/atomspace,Tiggels/opencog,cosmoharrigan/opencog,williampma/opencog,williampma/opencog,Allend575/opencog,AmeBel/atomspace,ceefour/opencog,kim135797531/opencog,MarcosPividori/atomspace,inflector/atomspace,rohit12/atomspace,gavrieltal/opencog,rohit12/opencog,yantrabuddhi/opencog,cosmoharrigan/atomspace,zhaozengguang/opencog,AmeBel/atomspace,TheNameIsNigel/opencog,cosmoharrigan/opencog,Selameab/opencog,kinoc/opencog,virneo/opencog,UIKit0/atomspace,kim135797531/opencog,iAMr00t/opencog,yantrabuddhi/opencog,inflector/opencog,printedheart/atomspace,printedheart/atomspace,jlegendary/opencog,misgeatgit/opencog,ceefour/opencog,AmeBel/opencog,tim777z/opencog,eddiemonroe/atomspace,AmeBel/opencog,rohit12/opencog,andre-senna/opencog,Selameab/opencog,ceefour/opencog,rTreutlein/atomspace,cosmoharrigan/atomspace,Selameab/opencog,sanuj/opencog,shujingke/opencog,ceefour/opencog