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Decorator module

Author: Michele Simionato
Requires:Python from 2.6 to 3.6
Download page:
Installation:pip install decorator
License:BSD license


If you are lazy, just perform

$ pip install decorator

which will install just the module on your system.

If you prefer to install the full distribution from source, including the documentation, clone the GitHub repo or download the tarball, unpack it and run

$ pip install .

in the main directory, possibly as superuser.


If you have the source code installation you can run the tests with

$ python src/tests/ -v

or (if you have setuptools installed)

$ python test

Notice that you may run into trouble if in your system there is an older version of the decorator module; in such a case remove the old version. It is safe even to copy the module over an existing one, since we kept backward-compatibility for a long time.


The project is hosted on GitHub. You can look at the source here:


The documentation has been moved to You can download a PDF version of it from

For the impatient

Here is an example of how to define a family of decorators tracing slow operations:

from decorator import decorator

def warn_slow(func, timelimit=60, *args, **kw):
    t0 = time.time()
    result = func(*args, **kw)
    dt = time.time() - t0
    if dt > timelimit:
        logging.warn('%s took %d seconds', func.__name__, dt)
    else:'%s took %d seconds', func.__name__, dt)
    return result

@warn_slow  # warn if it takes more than 1 minute
def preprocess_input_files(inputdir, tempdir):

@warn_slow(timelimit=600)  # warn if it takes more than 10 minutes
def run_calculation(tempdir, outdir):