order returns a permutation which rearranges its first argument
  into ascending or descending order, breaking ties by further
  arguments.  NOTE: This man page is for the order S4 generic function
  defined in the BiocGenerics package.
  See ?base::order for the default method
  (defined in the base package).
  Bioconductor packages can define specific methods for objects
  (typically vector-like) not supported by the default method.
order(..., na.last=TRUE, decreasing=FALSE, method=c("shell", "radix"))?base::order for a description of
    these arguments.
  ?base::order) returns
  an integer vector of length N where N is the common length of the
  input objects. This integer vector represents a permutation of N
  elements and can be used to rearrange the first argument in
  ... into ascending or descending order (by subsetting it).Specific methods defined in Bioconductor packages should also
  return an integer vector representing a permutation of N elements.
base::order for the default order method.
showMethods for displaying a summary of the
          methods defined for a given generic function.
selectMethod for getting the definition of
          a specific method.
order method (defined for
          Ranges objects).
order
showMethods("order")
selectMethod("order", "ANY")  # the default method
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