- mergeRoles(roleA: WRITABLE, roleB: READONLY_SIGNER): WRITABLE_SIGNER
- mergeRoles(roleA: READONLY_SIGNER, roleB: WRITABLE): WRITABLE_SIGNER
- mergeRoles(roleA: AccountRole, roleB: WRITABLE_SIGNER): WRITABLE_SIGNER
- mergeRoles(roleA: WRITABLE_SIGNER, roleB: AccountRole): WRITABLE_SIGNER
- mergeRoles(roleA: AccountRole, roleB: READONLY_SIGNER): READONLY_SIGNER
- mergeRoles(roleA: READONLY_SIGNER, roleB: AccountRole): READONLY_SIGNER
- mergeRoles(roleA: AccountRole, roleB: WRITABLE): WRITABLE
- mergeRoles(roleA: WRITABLE, roleB: AccountRole): WRITABLE
- mergeRoles(roleA: READONLY, roleB: READONLY): READONLY
- mergeRoles(roleA: AccountRole, roleB: AccountRole): AccountRole