import re
from bgpdumpy import BGPDump

with BGPDump( 'latest-bview.gz' ) as bgp:

    for entry in bgp:
    
        # entry.body can be either be TableDumpV1 or TableDumpV2
        
        if not isinstance( entry.body, TableDumpV2 ):
            continue  # I expect an MRT v2 table dump file
        
        # get a string representation of this prefix
        prefix = '%s/%d' %( entry.body.prefix, entry.body.prefixLength )
        
        # get a list of each unique originating ASN for this prefix
        originatingASs = set( [
            re.split( r'\s+', route.attr.asPath )[-1]
            for route
            in entry.body.routeEntries] )
        
        # just print it for demonstration purposes
        print( '%s -> %s' %( prefix, '/'.join( originatingASs ) ) )
        
# 1.0.0.0/24 -> 15169
# 1.0.4.0/24 -> 56203
# 1.0.5.0/24 -> 56203
# 1.0.6.0/24 -> 56203
# 1.0.7.0/24 -> 38803
# 1.0.38.0/24 -> 24155
# 1.0.64.0/18 -> 18144
# 1.0.128.0/17 -> 9737
# 1.0.128.0/18 -> 9737
# 1.0.128.0/19 -> 9737
# ...
# 2001::/32 -> 6939
# 2001:4:112::/48 -> 112
# 2001:200::/32 -> 2500
# 2001:200:900::/40 -> 7660
# 2001:200:c000::/35 -> 23634