ios parsing error for vlan ranges

If an ios config contains a range of vlans a parsing error is observed. 

Example config:

vlan 60
 name VLAN_A
!
vlan 64-65 
!
vlan 80
 name VLAN_B

Result: 

  File "/home/.local/lib/python3.7/site-packages/ntc_rosetta/parsers/openconfig/ios/openconfig_vlan/vlans.py", line 44, in vlan_id
    return int(self.yy.key)
ValueError: invalid literal for int() with base 10: '64-65'