code: function Caps(node, hash) {
    this.hash = (hash || 'sha-1').toLowerCase();
  
    if(this.hash !== 'sha-1') {
      throw new Error('Invalid argument provided for hash. Only sha-1 suported');
    }
  
    this.node = node;
    this.identities = [];
    this.features = [];
  }
docs: Capabilities
  
  @param {String} node Software identifier
  @param {String} [hash=sha-1] Hash to generate the version string (only sha-1 supported as of now)
  @constructor