# File lib/ldap/schema.rb, line 82
    def schema(base = nil, attrs = nil, sec = 0, usec = 0)
      attrs ||= [
        'objectClasses',
        'attributeTypes',
        'matchingRules',
        'matchingRuleUse',
        'dITStructureRules',
        'dITContentRules',
        'nameForms',
        'ldapSyntaxes',
      ]
      base ||= root_dse(['subschemaSubentry'], sec, usec)[0]['subschemaSubentry'][0]
      base ||= 'cn=schema'
      entries = search2(base, LDAP_SCOPE_BASE, '(objectClass=subschema)',
        attrs, false, sec, usec)

      return Schema.new(entries[0])
    end