diff --git a/doc/build.py b/doc/build.py

index 0943505b..59a7b498 100755

--- a/doc/build.py

+++ b/doc/build.py

@@ -7,16 +7,6 @@ from subprocess import check_call, check_output, CalledProcessError, Popen, PIPE

 versions = ['1.0.0', '1.1.0', '2.0.0', '3.0.2', '4.0.0', '4.1.0', '5.0.0', '5.1.0', '5.2.0', '5.2.1', '5.3.0', '6.0.0', '6.1.0', '6.1.1', '6.1.2', '6.2.0', '6.2.1', '7.0.0', '7.0.1', '7.0.2', '7.0.3', '7.1.0', '7.1.1', '7.1.2', '7.1.3']

-def create_build_env(dirname='virtualenv'):

-  # Create virtualenv.

-  if not os.path.exists(dirname):

-    check_call(['virtualenv', dirname])

-  import sysconfig

-  scripts_dir = os.path.basename(sysconfig.get_path('scripts'))

-  activate_this_file = os.path.join(dirname, scripts_dir, 'activate_this.py')

-  with open(activate_this_file) as f:

-    exec(f.read(), dict(__file__=activate_this_file))

-

 def build_docs(version='dev', **kwargs):

   doc_dir = kwargs.get('doc_dir', os.path.dirname(os.path.realpath(__file__)))

   work_dir = kwargs.get('work_dir', '.')

@@ -79,5 +69,4 @@ def build_docs(version='dev', **kwargs):

   return html_dir

 if __name__ == '__main__':

-  create_build_env()

   build_docs(sys.argv[1])

-- 

2.28.0