human
I wrote the below code

    from sympy.calculus.util import continuous_domain, periodicity, function_range
    from sympy.solvers.solvers import denoms
    from sympy.solvers.solveset import solveset_real, solvify
    d = Dummy(real=True)
    expr = expr.subs(gen, d)
    _gen = gen
    gen = d
    rv = None
    if (expr is S.true):
        rv = domain
    elif (expr is S.false):
        rv = S.EmptySet
    else:
        e = (expr.lhs - expr.rhs)
        period = periodicity(e, gen)
        if (period is not None):
            frange = function_range(e, gen, domain)
            rel = expr.rel_op
            if ((rel == '<') or (rel == '<=')):
                if expr.func(frange.sup, 0):
                    rv = domain
                elif (not expr.func(frange.inf, 0)):
                    rv = S.EmptySet
            elif ((rel == '>') or (rel == '>=')):
                if expr.func(frange.inf, 0):
                    rv = domain
                elif (not expr.func(frange.sup, 0)):
                    rv = S.EmptySet
            (inf, sup) = (domain.inf, domain.sup)
            if ((sup - inf) is S.Infinity):
                domain = Interval(0, period, False, True)
        if (rv is None):
            solns = solvify(e, gen, domain)
            if (solns is None):
                raise NotImplementedError(filldedent('The    inequality    cannot    be\n                                                                                solved    using    solve_univariate_inequality.'))
            singularities = []
            for d in denoms(expr, gen):
                singularities.extend(solvify(d, gen, domain))
            if (not continuous):
                domain = continuous_domain(e, gen, domain)
            include_x = expr.func(0, 0)
            def valid(x):
                v = e.subs(gen, x)
                try:
                    r = expr.func(v, 0)
                except TypeError:
                    r = S.false
                if (r in (S.true, S.false)):
                    return r
                if (v.is_real is...

What's a good function header?
assistant
#Here's a good function header.

def solve_univariate_inequality(expr, gen, relational=True, domain=S.Reals, continuous=False):