human
I wrote the below code

    cachekey = (integrand, symbol)
    if (cachekey in _integral_cache):
        if (_integral_cache[cachekey] is None):
            return None
        else:
            return _integral_cache[cachekey]
    else:
        _integral_cache[cachekey] = None
    integral = IntegralInfo(integrand, symbol)
    def key(integral):
        integrand = integral.integrand
        if isinstance(integrand, TrigonometricFunction):
            return TrigonometricFunction
        elif isinstance(integrand, sympy.Derivative):
            return sympy.Derivative
        elif (symbol not in integrand.free_symbols):
            return sympy.Number
        else:
            for cls in (sympy.Pow, sympy.Symbol, sympy.exp, sympy.log, sympy.Add, sympy.Mul, sympy.atan, sympy.asin, sympy.acos, sympy.Heaviside):
                if isinstance(integrand, cls):
                    return cls
    def integral_is_subclass(*klasses):
        def _integral_is_subclass(integral):
            k = key(integral)
            return (k and issubclass(k, klasses))
        return _integral_is_subclass
    result = do_one(null_safe(switch(key, {sympy.Pow: do_one(null_safe(power_rule), null_safe(inverse_trig_rule), null_safe(quadratic_denom_rule)), sympy.Symbol: power_rule, sympy.exp: exp_rule, sympy.Add: add_rule, sympy.Mul: do_one(null_safe(mul_rule), null_safe(trig_product_rule), null_safe(heaviside_rule), null_safe(quadratic_denom_rule), null_safe(root_mul_rule)), sympy.Derivative: derivative_rule, TrigonometricFunction: trig_rule, sympy.Heaviside: heaviside_rule, sympy.Number: constant_rule})), do_one(null_safe(trig_rule), null_safe(alternatives(rewrites_rule, substitution_rule, condition(integral_is_subclass(sympy.Mul, sympy.Pow), partial_fractions_rule), condition(integral_is_subclass(sympy.Mul, sympy.Pow), cancel_rule), condition(integral_is_subclass(sympy.Mul, sympy.log, sympy.atan, sympy.asin, sympy.acos), parts_rule), condition(integral_is_subclass(sympy.Mul, sympy.Pow), distribute_expand_rule), trig_powers_products_rule)),...

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

def integral_steps(integrand, symbol, **options):