There seems to be a new version of plotly (4.0) with additional functionalities, such as “add_lines”. See for example the example of this blog post: http://moderndata.plot.ly/macroeconomic-charts-by-the-fed-using-r-and-plotly/.
I installed the latest version of plotly from the github repository (development version), however I get the error: “Error in function_list[i] : could not find function “add_lines””.
Thank you, Valérie