 public enum ContentType {
     case json
     case formEncoded
+    case custom(String)
 }
 
 /// Converting to JSON error type

            return "application/json"
        case .formEncoded:
            return "application/x-www-form-urlencoded"
        }
    }
}

    internal func clientURLRequest(_ path: String, query: [String: Queryable]?, params: ValidRequestData?)
        -> URLRequest {
            var request = URLRequest(url: URL(string: baseURL + path, query: query))
            if let params = params, let httpData = try? params.requestData() {
                request.httpBody = httpData
                request.addValue(String(httpData.count), forHTTPHeaderField: "Content-Length")
            }
            
            headers.forEach() {
