Can I make instance methods not callable as static methods?
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2
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I have a @asynccontextmanager method named opened() that is an instance method of a class File. Sometimes I call it using a class by mistake like so File.opened(). It then fails because the object is not initialized (e.g. name) with an error that does not really express the problem.
AttributeError: 'str' object has no attribute 'opened'
Is there a way to prevent this?
Example
class File:
def __init__(self, file_name):
self.file_name = file_name
@asynccontextmanager
async def opened(self):
open(self.file_name)
# do other things
This should be OK:
file = File('input.csv')
async with file.opened() as file_handle:
#do stuff
But his should yield an error telling me that I can't use a instance method without creating an object first:
async with File.opened() as file_handle:
# does not work, and should not be allowed
python-3.x
asked Nov 9 at 19:06
problemofficer
365517
add a comment |
up vote
2
down vote
favorite
I have a @asynccontextmanager method named opened() that is an instance method of a class File. Sometimes I call it using a class by mistake like so File.opened(). It then fails because the object is not initialized (e.g. name) with an error that does not really express the problem.
AttributeError: 'str' object has no attribute 'opened'
Is there a way to prevent this?
Example
class File:
def __init__(self, file_name):
self.file_name = file_name
@asynccontextmanager
async def opened(self):
open(self.file_name)
# do other things
This should be OK:
file = File('input.csv')
async with file.opened() as file_handle:
#do stuff
But his should yield an error telling me that I can't use a instance method without creating an object first:
async with File.opened() as file_handle:
# does not work, and should not be allowed
python-3.x
asked Nov 9 at 19:06
problemofficer
365517
add a comment |
up vote
2
down vote
favorite
up vote
2
down vote
favorite
I have a @asynccontextmanager method named opened() that is an instance method of a class File. Sometimes I call it using a class by mistake like so File.opened(). It then fails because the object is not initialized (e.g. name) with an error that does not really express the problem.
AttributeError: 'str' object has no attribute 'opened'
Is there a way to prevent this?
Example
class File:
def __init__(self, file_name):
self.file_name = file_name
@asynccontextmanager
async def opened(self):
open(self.file_name)
# do other things
This should be OK:
file = File('input.csv')
async with file.opened() as file_handle:
#do stuff
But his should yield an error telling me that I can't use a instance method without creating an object first:
async with File.opened() as file_handle:
# does not work, and should not be allowed
python-3.x
asked Nov 9 at 19:06
problemofficer
365517
I have a @asynccontextmanager method named opened() that is an instance method of a class File. Sometimes I call it using a class by mistake like so File.opened(). It then fails because the object is not initialized (e.g. name) with an error that does not really express the problem.
AttributeError: 'str' object has no attribute 'opened'
Is there a way to prevent this?
Example
class File:
def __init__(self, file_name):
self.file_name = file_name
@asynccontextmanager
async def opened(self):
open(self.file_name)
# do other things
This should be OK:
file = File('input.csv')
async with file.opened() as file_handle:
#do stuff
But his should yield an error telling me that I can't use a instance method without creating an object first:
async with File.opened() as file_handle:
# does not work, and should not be allowed
python-3.x
python-3.x
asked Nov 9 at 19:06
problemofficer
365517
asked Nov 9 at 19:06
problemofficer
365517
asked Nov 9 at 19:06
problemofficer
365517
asked Nov 9 at 19:06
problemofficer
365517
asked Nov 9 at 19:06
problemofficer
365517
365517
add a comment |
add a comment |
1 Answer
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oldest
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up vote
1
down vote
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You can check if self is an instance of File so that you can raise an exception with a friendlier error message:
@asynccontextmanager
async def opened(self):
if not isinstance(self, File):
raise RuntimeError('opened() must be called as a method bound to a File instance.')
open(self.file_name)
answered Nov 9 at 19:23
blhsing
28.3k41335
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
accepted
You can check if self is an instance of File so that you can raise an exception with a friendlier error message:
@asynccontextmanager
async def opened(self):
if not isinstance(self, File):
raise RuntimeError('opened() must be called as a method bound to a File instance.')
open(self.file_name)
answered Nov 9 at 19:23
blhsing
28.3k41335
add a comment |
up vote
1
down vote
accepted
You can check if self is an instance of File so that you can raise an exception with a friendlier error message:
@asynccontextmanager
async def opened(self):
if not isinstance(self, File):
raise RuntimeError('opened() must be called as a method bound to a File instance.')
open(self.file_name)
answered Nov 9 at 19:23
blhsing
28.3k41335
add a comment |
up vote
1
down vote
accepted
up vote
1
down vote
accepted
You can check if self is an instance of File so that you can raise an exception with a friendlier error message:
@asynccontextmanager
async def opened(self):
if not isinstance(self, File):
raise RuntimeError('opened() must be called as a method bound to a File instance.')
open(self.file_name)
answered Nov 9 at 19:23
blhsing
28.3k41335
You can check if self is an instance of File so that you can raise an exception with a friendlier error message:
@asynccontextmanager
async def opened(self):
if not isinstance(self, File):
raise RuntimeError('opened() must be called as a method bound to a File instance.')
open(self.file_name)
answered Nov 9 at 19:23
blhsing
28.3k41335
answered Nov 9 at 19:23
blhsing
28.3k41335
answered Nov 9 at 19:23
blhsing
28.3k41335
answered Nov 9 at 19:23
blhsing
28.3k41335
28.3k41335
add a comment |
add a comment |
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