This module implements several useful functions and decorators that can be particularly useful for developers. E.g., deprecating methods / classes, etc.

deprecated(replacement=None, message=None)[source]

Decorator to mark classes or functions as deprecated, with a possible replacement.

  • replacement (callable) – A replacement class or method.

  • message (str) – A warning message to be displayed.


Original function, but with a warning to use the updated class.



If you are using Python >= 2.7, multiprocessing.cpu_count() already provides the number of CPUs. In fact, this is the first method tried. The purpose of this function is to cater to old Python versions that still exist on many Linux style clusters.

Number of virtual or physical CPUs on this system, i.e. user/real as output by time(1) when called with an optimally scaling userspace-only program. Return -1 if ncpus cannot be detected. Taken from: cpus-in-python

install_excepthook(hook_type='color', **kwargs)[source]

This function replaces the original python traceback with an improved version from Ipython. Use color for colourful traceback formatting, verbose for Ka-Ping Yee’s “” version kwargs are the keyword arguments passed to the constructor. See for more info.


0 if hook is installed successfully.

class requires(condition, message)[source]

Bases: object

Decorator to mark classes or functions as requiring a specified condition to be true. This can be used to present useful error messages for optional dependencies. For example, decorating the following code will check if scipy is present and if not, a runtime error will be raised if someone attempts to call the use_scipy function:

    import scipy
except ImportError:
    scipy = None

@requires(scipy is not None, "scipy is not present.")
def use_scipy():
  • condition – Condition necessary to use the class or function.

  • message – A message to be displayed if the condition is not True.

  • condition – A expression returning a bool.

  • message – Message to display if condition is False.