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__title__ = "FreeCAD FEM constant vacuum permittivity object"
__author__ = "Bernd Hahnebach"
__url__ = "https://www.freecad.org"

## @package constant_vacuumpermittivity
#  \ingroup FEM
#  \brief FreeCAD FEM constant vacuum permittivity object

from FreeCAD import Units

from femtools import constants
from . import base_fempythonobject


class ConstantVacuumPermittivity(base_fempythonobject.BaseFemPythonObject):

    Type = "Fem::ConstantVacuumPermittivity"

    def __init__(self, obj):
        super(ConstantVacuumPermittivity, self).__init__(obj)
        obj.addProperty(
            "App::PropertyVacuumPermittivity",
            "VacuumPermittivity",
            "Constants",
            "Overwrites default permittivity of vacuum"
        )
        # we must set an expression so that the small value can actually be entered
        permittivity = Units.Quantity(constants.vacuum_permittivity()).getValueAs("F/m")
        obj.setExpression("VacuumPermittivity", str(permittivity))