@staticmethod
def _deduce_system_type(**kwargs):
    """Based on the combination of arguments this returns which ODE
        description has been provided.

        full rhs
            x' = f(x, t, r, p)
        full mass matrix
            M(x, p) * x' = f(x, t, r, p)
        min mass matrix
            M(q, p) * u' = f(q, u, t, r, p)
            q' = g(q, u, t)

        """
    if kwargs.pop('coordinate_derivatives') is not None:
        system_type = 'min mass matrix'
    elif kwargs.pop('mass_matrix') is not None:
        system_type = 'full mass matrix'
    else:
        system_type = 'full rhs'
    return system_type
