md_bond query bond market data from FRED and ChinaBond.
md_bond(symbol = NULL, type = "history", date_range = "3y", from = NULL, to = Sys.Date(), print_step = 1L, ...)
bond symbols. Default is NULL.
the data type. Default is history.
date range. Available value includes '1m'-'11m', 'ytd', 'max' and '1y'-'ny'. Default is 3y.
the start date. Default is NULL. If it is NULL, then calculate using date_range and end date.
the end date. Default is the current date.
a non-negative integer, which will print symbol name by each print_step iteration. Default is 1L.