docs: def is_equal(self, other):
          """
          Computes whether two Partial Orderings contain the same information
          """
          if not (hasattr(other, 'get_domain') or hasattr(other, 'upper') or hasattr(other, 'lower')):
              other = self.coerce(other)
          if self.is_domain_equal(other)  \
              and len(self.upper.symmetric_difference(other.upper)) == 0 \
              and len(self.lower.symmetric_difference(other.lower)) == 0:
              return True
          return False