Creates a new file with the list of channels represented in the required format.
If the file already exists at the uri location, it is overwritten.
| this |
a FeedsGroup. |
| channels |
list of FeedChannels. |
| format |
string rappresenting the desired export format, as returnes by get_formats. |
| uri |
URI of the file to write. |
|
true if the file is created correctly, or false if an error occours and throws is set. |