Thanks for your comment. I must say they keep the above message in a place that is very difficult to see. Besides, I find that the hairpin structure they generated may be wrong. For example, for hsa-let-7a-1 (https://mirbase.org/hairpin/MI0000060) The sequence is
ugggaUGAGGUAGUAGGUUGUAUAGUUuuagggucacacccaccacugggagauaaCUAUACAAUCUACUGUCUUUCcua
(((((.(((((((((((((((((((((.....(((...((((....)))).)))))))))))))))))))))))))))))
While the structure is
U uuagg aca c
uggga GAGGUAGUAGGUUGUAUAGUU guc ccca c
||||| ||||||||||||||||||||| ||| ||||
aucCU UUCUGUCAUCUAACAUAUCaa uag gggu a
- ----- --a c
The third loop counting from the left seems to be wrong. From the dot bracket notation, aca corresponds to ... But in the diagram, aca is paired to --a but it should be ---
And I use a package called ViennaRNA (https://github.com/ViennaRNA/ViennaRNA/), which is also available on Python, to construct the dot-bracket structure for the sequence.