Community List Regex : space vs underscore

[rsingha108]

Describe the bug and expected behavior
I am trying to test some route-maps using the "Analyzing Routing Policies" Notebook. If we use the regex ^[0-1]:[1]+ [0-1]:[1-2]+$, it doesn't match with the community "0:1 0:12" but if we use the regex ^[0-1]:[1]+_[0-1]:[1-2]+$ (' ' replaced by '_'), it matches. Ideally the regex with ' ' should also match.

Runnable example

Configuration file in networks/route-analysis/configs/border3.cfg

!
hostname border3
!
ip community-list 100 permit ^[0-1]:[1]+ [0-1]:[1-2]+$
!
route-map Rmap permit 10
	match community 100
!
end

python code in notebooks/Analyzing Routing Policies

%run startup.py
from pybatfish.datamodel.route import BgpRouteConstraints
bf = Session(host="localhost")

# Initialize a network and snapshot
NETWORK_NAME = "example_network"
SNAPSHOT_NAME = "example_snapshot"

SNAPSHOT_PATH = "networks/route-analysis"

bf.set_network(NETWORK_NAME)
bf.init_snapshot(SNAPSHOT_PATH, name=SNAPSHOT_NAME, overwrite=True)

# Create an example route to use for testing
inRoute1 = BgpRoute(network="10.0.0.0/24", 
                    originatorIp="4.4.4.4", 
                    originType="egp", 
                    protocol="bgp",
                    communities=["0:1","0:12"])

# Test how our policy treats this route
result = bf.q.testRoutePolicies(policies="Rmap", 
                             direction="in", 
                             inputRoutes=[inRoute1]).answer().frame()
# Pretty print the result
show(result)

Additional context
The expected output is PERMIT but the output is DENY. If we change the ' ' in regex to '_' the the output is PERMIT (as expected)