def addVariantFeature(self,variantFeature):
        '''Appends one VariantFeature to variantFeatures
        '''
        if isinstance(variantFeature, Feature):
            self.features.append(variantFeature)
        else:
            raise(TypeError,
                  'variantFeature Type should be Feature, not %s' % type(
                    variantFeature)
                  )
Appends one VariantFeature to variantFeatures