docs: def getValue(self, prop, default=None):
          """Return the value of feature with that name or ``default``."""
  
          f = self.props.get(prop, None)
          if not f:
              return default
          if isinstance(f, Feature):
              return f.getValue()
          if isinstance(f, tuple):
              # if f[0].getValue() == f[1].getValue():
              #    return f[0].getValue()
              # Miguel: para poder probar
              if f[0]:
                  return f[0].getValue()
              elif f[1]:
                  return f[1].getValue()
              raise Exception("Getting value from a property with a constrain")
          return f