Retrieve string for indelcaller to use, or empty string if not specified.

def get_indelcaller(d_or_c):
    """Retrieve string for indelcaller to use, or empty string if not specified.
    """
    config = d_or_c if isinstance(d_or_c, dict) and "config" in d_or_c else d_or_c
    indelcaller = config["algorithm"].get("indelcaller", "")
    if not indelcaller:
        indelcaller = ""
    if isinstance(indelcaller, (list, tuple)):
        indelcaller = indelcaller[0] if (len(indelcaller) > 0) else ""
    return indelcaller