def hfsym(self, kcn="", xkey="", ykey="", zkey="", **kwargs):
    """Indicates the presence of symmetry planes for the computation of

    APDL Command: HFSYM
    acoustic fields in the near and far field domains (beyond the finite
    element region).

    Parameters
    ----------
    kcn
        Coordinate system reference number. KCN may be 0 (Cartesian), or
        any previously defined local Cartesian coordinate system number
        (>10). Defaults to 0.

    xkey
        Key for acoustic field boundary condition, as prescribed for the
        solution, corresponding to the x = constant plane:

        None - No sound soft or sound hard boundary conditions (default).

        SSB - Sound soft boundary (pressure = 0).

        SHB - Sound hard boundary (normal velocity = 0).

    ykey
        Key for acoustic field boundary condition, as prescribed for the
        solution, corresponding to the y = constant plane:

        None - No sound soft or sound hard boundary conditions (default).

        SSB - Sound soft boundary (pressure = 0).

        SHB - Sound hard boundary (normal velocity = 0).

    zkey
        Key for acoustic field boundary condition, as prescribed for the
        solution, corresponding to the z = constant plane:

        None - No sound soft or sound hard boundary conditions (default).

        SSB - Sound soft boundary (pressure = 0).

        SHB - Sound hard boundary (normal velocity = 0).

    Notes
    -----
    HFSYM uses the image principle to indicate symmetry planes (x, y, or z
    = constant plane) for acoustic field computations outside the modeled
    domain. A sound hard boundary condition must be indicated even though
    it occurs as a natural boundary condition.

    No menu paths are available for acoustic applications.
    """
    command = f"HFSYM,{kcn},{xkey},{ykey},{zkey}"
    return self.run(command, **kwargs)