code: def import_from(self, other_ns, replace=False):
          
          for other_ns_uri in other_ns.namespace_uris:
              ni = self.__ns_uri_map.get(other_ns_uri)
  
              if ni is None:
                  other_ni = other_ns._NamespaceSet__ns_uri_map[other_ns_uri]
  
                  # Gotta make sure that the other set isn't mapping its prefixes
                  # incompatibly with respect to this set.
                  for other_prefix in other_ni.prefixes:
                      self.__check_prefix_conflict(other_ns_uri, other_prefix)
  
                  cloned_ni = copy.deepcopy(other_ni)
                  self.__add_namespaceinfo(cloned_ni)
              elif replace:
                  other_ni = other_ns._NamespaceSet__ns_uri_map[other_ns_uri]
                  for other_prefix in other_ni.prefixes:
                      self.__check_prefix_conflict(ni, other_prefix)
  
                  cloned_ni = copy.deepcopy(other_ni)
                  self.remove_namespace(other_ns_uri)
                  self.__add_namespaceinfo(cloned_ni)
              else:
                  continue
docs: Imports namespaces into this set, from other_ns.
  
          Args:
              other_ns (NamespaceSet): The set to import from
              replace (bool): If a namespace exists in both sets, do we replace
                  our data with other_ns's data?  We could get fancy and define
                  some merge strategies, but for now, this is very simple.  It's
                  either do nothing, or wholesale replacement.  There is no
                  merging.
  
          Raises:
              DuplicatePrefixError: If the other NamespaceSet is mapping any
                  prefixes incompatibly with respect to this set.