code: 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)
                    f 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)
                    )
docs: Appends one VariantFeature to variantFeatures