def METHOD_NAME() -> Symbol:
    """
    Symbolic constant: one
    :return: 1
    :rtype: symbolic
    .. runblock:: pycon
        >>> from spatialmath.base.symbolic import *
        >>> x = symbol('x')
        >>> one()
        >>> one() * x
    :seealso: :func:`sympy.S.One`
    """
    return sympy.S.One