python maya get min max key frame

def GetAllByType(selType="joint"):
    all_curves = cmds.ls(type=selType, ni=True, o=True, r=True, l = True)
    curves_transforms = cmds.listRelatives(all_curves, p=True, type = "transform")
    return curves_transforms


def GetMinMaxFrame(selType="joint"):
    import math
    joints = GetAllByType(selType)
    minKey = 10000
    maxKey = 0
    for joint in joints:
        all_keys = sorted(cmds.keyframe(joint, q=True) or [])  # Get all the keys and sort them by order. We use `or []` in-case it has no keys, which will use an empty list instead so it doesn't crash `sort`.
        if all_keys:  # Check to see if it at least has one key.
            if all_keys[0] < minKey: minKey = all_keys[0]
            if all_keys[-1] > maxKey: maxKey = all_keys[-1]
    return math.floor(minKey), math.ceil(maxKey)
min, max = GetMinMaxFrame()
print(min, max)