docs: def validate(self, value):
          """
          Accepts: float, int, long, str, unicode
          Returns: float
          """
          if isinstance(value, (str, unicode, int, long)):
              value = float(value)
          value = super(Float, self).validate(value)
          if not isinstance(value, (float)):
              raise ValueError("Not an float: %r" % (value, ))
          return value