Problems with a get request via RestClient in Groovy - api

Question

I'm new to Groovy and a bit rusty on development.
I am trying to make a GET request to a woocommerce API. With Postman it works OK but not in Groovy it is not entirely clear to me what you need to cast from String to Map Entry.
I imagine it's something relatively simple but I can't find it.
Thanks a lot.
#Grab('com.github.groovy-wslite:groovy-wslite:1.1.2')
import groovy.json.JsonSlurper
import wslite.rest.*
def request
RESTClient client = new RESTClient("https://www.somewoomcersite.com")
def path = "/wp-json/wc/v3/customers"
request = client.get(path: path, headers: ["Authorization", "BLA BLA"])
Caught: java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Map$Entry
java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Map$Entry
at wslite.rest.RESTClient.createRequestParams(RESTClient.groovy:118)
at wslite.rest.RESTClient.this$2$createRequestParams(RESTClient.groovy)
at wslite.rest.RESTClient.executeMethod(RESTClient.groovy:93)
at wslite.rest.RESTClient.this$2$executeMethod(RESTClient.groovy)
at wslite.rest.RESTClient.get(RESTClient.groovy:49)
at wslite.rest.RESTClient.get(RESTClient.groovy)
at wslite.rest.RESTClient$get.call(Unknown Source)
at MAG.run(MAG.groovy:9)
An example json of the response would be this:
https://woocommerce.github.io/woocommerce-rest-api-docs/#list-all-customers