IndexError: too many indices for array: array is 0-dimensional, but 1 were indexed

[fridayorji]

I need help for this error message when I run the following python code on a Windows 10 machine:

config = f"""
[DataSource1]
mappings=rules3_mapping.r2rml.ttl
db_url=mysql+pymysql://root:Kaboyacci3143@localhost/webgov
"""

import kglab

namespaces = {
"rv": "http://WebGov.RiversState.gov.ng/",
}

kg = kglab.KnowledgeGraph(
name = "RV WebGov KG",
namespaces = namespaces
)

kg.materialize(config)

save RDF as ttl

kg.save_rdf("rdf-triples33.ttl")

save RDF as jsonld

kg.save_jsonld("rdf-triples33.jsonld")

The yaml file that's parsed to obtain the rules3_mapping.r2rml.ttl is as follows:

prefixes:
rv: "http://WebGov.RiversState.gov.ng/"

sources:
citizens:
queryFormulation: mysql
query: select * from citizen

mappings:
citizen:
sources: citizens
s: http://WebGov.RiversState.gov.ng/$(citizenid)
po:
- [a, rv:citizen]
- [rv:firstname, $(FirstName)]
- [rv:lastname, $(LastName)]
- [rv:dateofbirth, $(Date_Of_Birth)]
- [rv:sex, $(Sex)]

Can anyone help?