code: def build_traversal(self, traversal):
          
          # build source
          rhs_label = ':' + traversal.target_class.__label__
  
          # build source
          lhs_ident = self.build_source(traversal.source)
          rhs_ident = traversal.name + rhs_label
          self._ast['return'] = traversal.name
          self._ast['result_class'] = traversal.target_class
  
          rel_ident = self.create_ident()
          stmt = _rel_helper(lhs=lhs_ident, rhs=rhs_ident, ident=rel_ident, **traversal.definition)
          self._ast['match'].append(stmt)
  
          if traversal.filters:
              self.build_where_stmt(rel_ident, traversal.filters)
  
          return traversal.name
docs: traverse a relationship from a node to a set of nodes