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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 exec_(name, command, runas=None):
    '''
    Run a command on a VM

    :param str name:
        Name/ID of VM whose exec will be returned

    :param str command:
        Command to run on the VM

    :param str runas:
        The user that the prlctl command will be run as

    Example:

    .. code-block:: bash

        salt '*' parallels.exec macvm 'find /etc/paths.d' runas=macdev
    '''
    # Construct argument list
    args = [salt.utils.data.decode(name)]
    args.extend(_normalize_args(command))

    # Execute command and return output
    return prlctl('exec', args, runas=runas)