Concept.prototype.displayResults = function(emailsList){
   Promise.map(emailsList, function (email, i) {
      return this.fetchImageURL(email).then(imageURL => {
        return this.checkFaceExistence(imageURL)
      }).then(exists => {
        console.log("User with email:", email, "and index:", i, "has/hasn't face in his profile picture", exists)
      }).catch(error => {
        // Error occured
      });
   });
}