def build_role(uid, scu_role=False, scp_role=False):
    """Return a SCP/SCU Role Selection Negotiation item.

    Parameters
    ----------
    uid : str or UID or sop_class.SOPClass
        The UID or SOPClass instance to use as the *SOP Class UID* parameter
        value.
    scu_role : bool, optional
        True to propose the SCU role for the *Requestor*, False otherwise
        (default).
    scp_role : bool, optional
        True to propose the SCP role for the *Requestor*, False otherwise
        (default).

    Returns
    -------
    pdu_primitives.SCP_SCU_RoleSelectionNegotiation
        The role selection item.
    """
    from pynetdicom.pdu_primitives import SCP_SCU_RoleSelectionNegotiation
    role = SCP_SCU_RoleSelectionNegotiation()
    role.sop_class_uid = uid
    role.scu_role = scu_role
    role.scp_role = scp_role
    return role
