Minor cleanup

README.rst

@@ -142,14 +142,14 @@ You can customize while initializing a tracer.
     from opencensus.trace import file_exporter
     from opencensus.trace import tracer as tracer_module
     from opencensus.trace.propagation import google_cloud_format
-    from opencensus.trace.samplers import probability
+    from opencensus.trace.samplers import ProbabilitySampler
 
     config_integration.trace_integrations(['httplib'])
 
     tracer = tracer_module.Tracer(
         exporter=file_exporter.FileExporter(file_name='traces'),
         propagator=google_cloud_format.GoogleCloudFormatPropagator(),
-        sampler=probability.ProbabilitySampler(rate=0.5),
+        sampler=ProbabilitySampler(rate=0.5),
     )
 
     with tracer.span(name='parent'):

nox.py

@@ -129,8 +129,12 @@ def lint(session):
 
     session.run(
         'flake8',
-        '--exclude=contrib/opencensus-ext-ocagent/opencensus/ext/ocagent/trace_exporter/gen/',
-        'context/', 'contrib/', 'opencensus/', 'tests/', 'examples/')
+        'context/',
+        'contrib/',
+        'opencensus/',
+        'tests/',
+        'examples/',
+    )
 
 
 @nox.session

setup.py

@@ -25,7 +25,7 @@
     author_email='census-developers@googlegroups.com',
     classifiers=[
         'Intended Audience :: Developers',
-        'Development Status :: 3 - Alpha',
+        'Development Status :: 4 - Beta',
         'Intended Audience :: Developers',
         'License :: OSI Approved :: Apache Software License',
         'Programming Language :: Python',
@@ -35,6 +35,7 @@
         'Programming Language :: Python :: 3.4',
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
     ],
     description='A stats collection and distributed tracing framework',
     include_package_data=True,