code: def validate(self):
          
          validate_edge_direction(self.direction)
          validate_safe_string(self.edge_name)
  
          if not isinstance(self.within_optional_scope, bool):
              raise TypeError(u'Expected bool within_optional_scope, got: {} '
                              u'{}'.format(type(self.within_optional_scope).__name__,
                                           self.within_optional_scope))
  
          if not isinstance(self.depth, int):
              raise TypeError(u'Expected int depth, got: {} {}'.format(
                  type(self.depth).__name__, self.depth))
  
          if not (self.depth >= 1):
              raise ValueError(u'depth ({}) >= 1 does not hold!'.format(self.depth))
docs: Ensure that the Traverse block is valid.