好的，我认为这样的代码不会出错，但它显然会：
somewhere:
# p is a float value between 0 and 1
m.limit=PidRange(p-1.0, p+1.0)
class PidRange(Range):
def __init__(self, low, up):
Range.__init__(low,up,...)
pass
# some methods definition for the PidRange sub-class
class Range(object):
def __init__(self, p_min=None, p_max=None, ...):
if (p_min > p_max):
raise ValueError("Range can't be created: the low bound %f exceeds high bound %f."%(p_min,p_max))
我只是想用一些类层次结构初始化一个 [min,max] 范围。但是由于一些完全奇怪的原因， p=0.888337 会引发以下异常：
File "src/__main__.py", line 155, in __find_data
m.limit=PidRange(p-1.0, p+1.0)
File "src/routing.py", line 32, in __init__
Range.__init__(low, up, low!=None, up!=None)
File "src/equation.py", line 30, in __init__
raise ValueError("Range can't be created: the low bound %f exceeds high bound %f."%(p_min,p_max))
ValueError: Range can't be created: the low bound 1.888337 exceeds high bound 1.000000.
有人知道发生了什么吗？我不得不承认我离掌握 Python 语言还很远，但我看不到任何可以解释这种奇怪行为的微妙之处。