Tweak tsibble -> epi_df example explanation

Author: lcbrooks

R/epi_df.R

@@ -115,8 +115,6 @@ NULL
 #' # Convert a `tsibble` that has county code as an extra key
 #' # Notice that county code should be a character string to preserve any leading zeroes
 #' 
-#' # `other_keys` are specified in the `key` parameter 
-#' # in the `as_tsibble()` function, along with the primary key
 #' ex1_input <- tibble::tibble(
 #'   geo_value = rep(c("ca", "fl", "pa"), each = 3),
 #'   county_code = c("06059","06061","06067",
@@ -128,8 +126,12 @@ NULL
 #' ) %>% 
 #'   tsibble::as_tsibble(index = time_value, key = c(geo_value, county_code))
 #' 
+#' # The `other_keys` metadata (`"county_code"` in this case) is automatically
+#' # inferred from the `tsibble`'s `key`:
 #' ex1 <- as_epi_df(x = ex1_input, geo_type = "state", time_type = "day", as_of = "2020-06-03")
-#' attr(ex1,"metadata")
+#' attr(ex1,"metadata")[["other_keys"]]
+#' 
+#' 
 #' 
 #' # Dealing with misspecified column names:
 #' # Geographical and temporal information must be provided in columns named
@@ -153,6 +155,8 @@ NULL
 #' 
 #' attr(ex2,"metadata")
 #' 
+#' 
+#' 
 #' # Adding additional keys to an `epi_df` object
 #' 
 #' ex3_input <- jhu_csse_county_level_subset %>%