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raise TypeError('was immer als text sinn macht')

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try:
    # irgendwas das einen TypeError auslösen kann
except TypeError as error:
    # Hier *sinnvoll* (das ist *ganz* wichtig!) auf die Ausnahme reagieren

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from __future__ import absolute_import, division, print_function
try:
    from functools import singledispatch
except ImportError:
    from singledispatch import singledispatch


@singledispatch
def nested_sum(item):
    raise TypeError('unexpected value of type {0.__name__}'.format(type(item)))



def identity(item):
    return item


nested_sum.register(int, identity)


try:
    nested_sum.register(long, identity)
except NameError:
    pass  # Python >2 has no `long` type anymore.


@nested_sum.register(list)
def _(items):
    return sum(nested_sum(item) for item in items)


def main():
    print(nested_sum(42))
    print(nested_sum([1, 2, [4711, 23], 42]))
    print(nested_sum(1000000000000000000000000000000000000))
    print(nested_sum(None))


if __name__ == '__main__':
    main()

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def nested_sum(l):
    try:
        if not isinstance(l, list):
                    raise TypeError
    except TypeError:
            print 'no list'
    
    i = 0
    for e in l:
        try:
            if not isinstance(e, list):
                    raise TypeError
        except TypeError:
            print 'no list'
        
        i1 = 0
        for e1 in e:
            try:
                if not isinstance(e1, int):
                    raise TypeError
            except TypeError:
                print 'no integer'
            i1 += e1
        i += i1
    return i

l = [['willi',2,2],[3,3,3],[4,4,4]]
print nested_sum(l)

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def nested_sum(l):
    try:
        if not isinstance(l, list):
                    raise TypeError
    except TypeError:
            return 'no list'
    
    i = 0
    for e in l:
        try:
            if not isinstance(e, list):
                    raise TypeError
        except TypeError:
            return 'no list'
        
        i1 = 0
        for e1 in e:
            try:
                if not isinstance(e1, int):
                    raise TypeError
            except TypeError:
                return 'no integer'
            i1 += e1
        i += i1
    return i

l = [[2,2,2],[3,3,3],7]
print nested_sum(l)
l = [['willi',2,2],[3,3,3],[4,4,4]]
print nested_sum(l)
l = [[2,2,2],[3,3,3],[4,4,4]]
print nested_sum(l)
l = 'willi'
print nested_sum(l)

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a = 3.5 # das ist keine Integer
a & 1 # und das geht dann nicht und wirft eine Exception

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a = 3.5
try:
    a & 1
except TypeError:
    print("Warum war das keine Integer, aber egal, ich mache weiter")

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a = 3.5
try:
    a & 1
except TypeError:
   print("Wieder keine Integer, ich gebe es jetzt endlich auf")
   raise

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a = True
if istype(a,bool):
    a = 3.5
a & 1

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if not isinstance(l, list):
    3.5 & 1

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In [1]: isinstance(True, int)
Out[1]: True

In [2]: isinstance(False, int)
Out[2]: True

In [3]: issubclass(bool, int)
Out[3]: True

In [4]: True + True
Out[4]: 2

In [5]: 42 / False
---------------------------------------------------------------------------
ZeroDivisionError                         Traceback (most recent call last)
<ipython-input-5-5e0a6f844f47> in <module>()
----> 1 42 / False

ZeroDivisionError: integer division or modulo by zero

In [6]: -True
Out[6]: -1