code: def equals(self, that, include_ref=False, fref=None):
          
          if not include_ref:
              # return the result of WDBaseDataType.__eq__, which is testing for equality of value and qualifiers
              return self == that
          if include_ref and self != that:
              return False
          if include_ref and fref is None:
              fref = WDBaseDataType.refs_equal
          return fref(self, that)
docs: Tests for equality of two statements.
          If comparing references, the order of the arguments matters!!!
          self is the current statement, the next argument is the new statement.
          Allows passing in a function to use to compare the references 'fref'. Default is equality.
          fref accepts two arguments 'oldrefs' and 'newrefs', each of which are a list of references,
          where each reference is a list of statements