The default server at the start of a new session is the practice server.
Call this function to switch to the live server.
This function can be used to toggle between the practice and live servers.
Any cached variables for API key, account or instruments list are cleared
each time this function is called.
For further details please refer to the OANDA fxTrade API vignette by
calling: vignette("xoanda", package = "ichimoku")
.