Given the following python code:

def one_dna_to_rna(c): """function takes a single-character string c representing a DNA nucleotide and returns the corresponding messenger-RNA nucleotide.""" assert(len(c) == 1) if c == 'A': return 'U' if c == 'C': return 'G' if c == 'G': return 'C' if c == 'T': return 'A' elif c not in 'ACGT': return ' '

write a function called transcribe(s) that takes as input a string s representing a piece of DNA, and that uses recursion to construct and return a string representing the corresponding RNA. Any characters in the input that dont correspond to a DNA nucleotide should not appear in the returned RNA string.