Hey, I want to select heterozygotes of one sample from a variant VCF file

for the homozygote selection, we used the follows,

$ java -Xmx4g -jar GenomeAnalysisTK.jar -T SelectVariants -R reference.fa --mysnp.vcf -select 'vc.getGenotype("sampleID").isHomVar()' -o output.vcf &

however, I use the commands as follows for heterozygote, it did not work

$ java -Xmx4g -jar GenomeAnalysisTK.jar -T SelectVariants -R genome.fa --variant 417snp.vcf -select 'vc.getGenotype("M895_417").isHerVar()' -o 417het.vcf

Did i miss something? I can not find the documents how to select heterozygotes.

Thanks