Utility methods.
| Function | getProcessOutput | Spawn a process and return its output as a deferred returning a bytes. | 
| Function | getProcessValue | Spawn a process and return its exit code as a Deferred. | 
| Function | getProcessOutputAndValue | No summary | 
| Function | runWithWarningsSuppressed | Run the function f, but with some warnings suppressed. | 
| Function | suppressWarnings | Wrap fin a callable which suppresses the indicated 
warnings before invokingfand unsuppresses them afterwards.  
If f returns a Deferred, warnings will remain suppressed until the Deferred
fires. | 
| Function | _callProtocolWithDeferred | Undocumented | 
| Class | _UnexpectedErrorOutput | Standard error data was received where it was not expected.  This is a 
subclass of IOErrorto preserve backward compatibility with the previous error behavior ofgetProcessOutput. | 
| Class | _BackRelay | Trivial protocol for communicating with a process and turning its output
into the result of a Deferred. | 
| Class | _ValueGetter | Undocumented | 
| Class | _EverythingGetter | Undocumented | 
| Function | _resetWarningFilters | Undocumented | 
Spawn a process and return its output as a deferred returning a bytes.
| Parameters | executable | The file name to run and get the output of - the full path should be used. | 
| args | the command line arguments to pass to the process; a sequence of strings. The first string should NOT be the executable's name. | |
| env | the environment variables to pass to the process; a dictionary of strings. | |
| path | the path to run the subprocess in - defaults to the current directory. | |
| reactor | the reactor to use - defaults to the default reactor | |
| errortoo | If true, include stderr in the result.  If false, if stderr is received the
returned Deferredwill 
errback with anIOErrorinstance with aprocessEndedattribute.  TheprocessEndedattribute refers to aDeferredwhich
fires when the executed process ends. | 
Spawn a process and return its exit code as a Deferred.
Spawn a process and returns a Deferred that will be called back with its output (from stdout and stderr) and it's exit code as (out, err, code) If a signal is raised, the Deferred will errback with the stdout and stderr up to that point, along with the signal, as (out, err, signalNum)