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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 _get_conda_channels(conda_bin):
 """Retrieve default conda channels, checking if they are pre-specified in config. This allows users to override defaults with specific mirrors in their .condarc """

    channels = ["bioconda", "conda-forge"]
    out = []
    config = yaml.safe_load(subprocess.check_output([conda_bin, "config", "--show"]))
    for c in channels:
        present = False
        for orig_c in config.get("channels") or []:
            if orig_c.endswith((c, "%s/" % c)):
                present = True
                break
        if not present:
            out += ["-c", c]
    return out