Construct a ``Steerer`` instance from the Pynac lattice element

def from_dynacRepr(cls, pynacRepr):
        """
        Construct a ``Steerer`` instance from the Pynac lattice element
        """
        f = float(pynacRepr[1][0][0])
        p = 'HV'[int(pynacRepr[1][0][1])]
        return cls(f, p)