code: func GetPolicies(mspIDs ...string) (signedBy []*common.SignaturePolicy, identities []*mb.MSPPrincipal, err error) {
  	for i, mspID := range mspIDs {
  		signedBy = append(signedBy, NewSignedByPolicy(int32(i)))
  		principal, err := NewPrincipal(mspID, mb.MSPPrincipal_ROLE)
  		if err != nil {
  			return nil, nil, err
  		}
  		identities = append(identities, principal)
  	}
  	return
  }
docs: // GetPolicies creates a set of 'signed by' signature policies and corresponding identities for the given set of MSP IDs