 
   @doc """
   Returns the string representation of the given `Sippet.URI` struct.
+
+  ## Examples
+
       iex> Sippet.URI.to_string(Sippet.URI.parse("sip:foo@bar.com"))
       "sip:foo@bar.com"
       iex> Sippet.URI.to_string(%URI{scheme: "foo", host: "bar.baz"})


  @doc """
  Parses a well-formed SIP-URI reference into its components.
  Note this function expects a well-formed SIP-URI and does not perform
  any validation. See the "Examples" section below for examples of how
  `Sippet.URI.parse/1` can be used to parse a wide range of URIs.

  Returns the default port for a given SIP scheme.
  If the scheme is unknown to the `Sippet.URI` module, this function returns
  `nil`.

  ## Examples

      iex> Sippet.URI.default_port("sip")
      5060
      iex> Sippet.URI.default_port("ponzi")
