The 'midi==0.2.3' distribution was not found and is required by the application

[johnguacala]

When I try to read a mididump.py mary.midi shows this error

Traceback (most recent call last):
File "C:\ProgramData\Anaconda3\envs\tweetproject\Scripts\mididump.py", line 4, in
import('pkg_resources').run_script('midi==0.2.3', 'mididump.py')
File "C:\Python27\lib\site-packages\pkg_resources_init_.py", line 3126, in
@call_aside
File "C:\Python27\lib\site-packages\pkg_resources_init.py", line 3110, in call_aside
f(*args, **kwargs)
File "C:\Python27\lib\site-packages\pkg_resources_init.py", line 3139, in initialize_master_working_set
working_set = WorkingSet.build_master()
File "C:\Python27\lib\site-packages\pkg_resources_init.py", line 581, in build_master
ws.require(requires)
File "C:\Python27\lib\site-packages\pkg_resources_init.py", line 898, in require
needed = self.resolve(parse_requirements(requirements))
File "C:\Python27\lib\site-packages\pkg_resources_init.py", line 784, in resolve
raise DistributionNotFound(req, requirers)
pkg_resources.DistributionNotFound: The 'midi==0.2.3' distribution was not found and is required by the application

anyone knowa what does it means?