Pyan3 in a container not working.

[AIBappa]

Using following versions:
pyan3==1.1.1
python:3.7

Running following file to do a callgraph on all the files in the app folder.
import pyan

callgraph = pyan.create_callgraph('/app/**/*.py', format='dot')

with open('trial1.dot', 'w') as f:
f.write(callgraph)

Get an error as follows:
root@3463e99ee9fb:/test# python checkdep.py
Traceback (most recent call last):
File "checkdep.py", line 3, in
callgraph = pyan.create_callgraph('../app/**/*.py', format='dot')
File "/usr/local/lib/python3.7/site-packages/pyan/init.py", line 72, in create_callgraph
v = CallGraphVisitor(filenames)
File "/usr/local/lib/python3.7/site-packages/pyan/analyzer.py", line 75, in init
self.process()
File "/usr/local/lib/python3.7/site-packages/pyan/analyzer.py", line 82, in process
self.process_one(filename)
File "/usr/local/lib/python3.7/site-packages/pyan/analyzer.py", line 96, in process_one
self.visit(ast.parse(content, filename))
File "/usr/local/lib/python3.7/ast.py", line 271, in visit
return visitor(node)
File "/usr/local/lib/python3.7/site-packages/pyan/analyzer.py", line 340, in visit_Module
self.generic_visit(node) # visit the children of node
File "/usr/local/lib/python3.7/ast.py", line 279, in generic_visit
self.visit(item)
File "/usr/local/lib/python3.7/ast.py", line 271, in visit
return visitor(node)
File "/usr/local/lib/python3.7/site-packages/pyan/analyzer.py", line 752, in visit_AnnAssign
get_ast_node_name(value[0]),
IndexError: list index out of range