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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 search_carts(env, pkg_name, repos):
 """ returns a list of carts containing a package with the specified name env: the name of an environment from the juicer config pkg_name: the name of the package for which to search repos: a list of repos in which to search for the package """

    db = cart_db()
    carts = db[env]

    for repo in repos:
        field = 'repos_items.%s' % repo
        value = '.*%s.*' % pkg_name

        found_carts = []

        for cart in carts.find({field: {'$regex': value}}):
            found_carts.append(cart)
        return found_carts