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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def find_otu(otuid, tree):
 """ Find an OTU ID in a Newick-format tree. Return the starting position of the ID or None if not found. """

    for m in re.finditer(otuid, tree):
        before, after = tree[m.start()-1], tree[m.start()+len(otuid)]
        if before in ["(", ",", ")"] and after in [":", ";"]:
            return m.start()
    return None