def _set_value(self, value):
        """
        set the value
        """
        if value is None:
            self._value = value
            return

        # handle casting to acceptable types
        if isinstance(value, list) or isinstance(value, tuple):
            value = np.array(value)
        if isinstance(value, int):
            value = float(value)
        if isinstance(value, u.Quantity):
            if self.unit == u.dimensionless_unscaled:
                # then take the unit from quantity and apply it
                self.unit = value.unit
                value = value.value
            else:
                # then convert to the requested unit
                value = value.to(self.unit).value

        # handle setting based on type
        if isinstance(value, np.ndarray):
            # if len(value.shape) != 1:
                # raise ValueError("value must be a flat array")

            self._value = value
        elif isinstance(value, float):
            # TODO: do we want to cast to np.array([value])??
            # this will most likely be used for axhline/axvline
            self._value = value
        # elif isinstance(value, str):
            # TODO: then need to pull from the bundle??? Or will this happen
            # at a higher level
        elif self.direction=='c' and isinstance(value, str):
            self._value = common.coloralias.map(value)
        else:
            raise TypeError("value must be of type array (or similar)")
set the value