class D[K, T](dict[K, T]):
  """
  An almost-standard `dict` that does not include in its items properties 
  named `warnings` if their value is an empty list, meaning it will not
  be present when being converted to JSON
  """
  def items(self) -> typing.Any:
    for k in self.keys():
      v = self[k]
      if k != 'warnings' or (isinstance(v, list) and len(v) != 0):
        yield k, v

def build_affected_range(constraint: str) -> osv.Range:
  events, warnings = parse_version_constraint(constraint)

  return {
    'type': 'ECOSYSTEM',
    'events': events,
    'database_specific': D({'constraint': constraint, 'warnings': warnings})
  }