code: public java.util.Map<String, java.util.List<String>> getAttributes() {
          return attributes;
      }
docs: Custom attributes that describe the endpoint by associating a name with an array of values. For example, an
  attribute named "interests" might have the values ["science", "politics", "travel"]. You can use these attributes
  as selection criteria when you create a segment of users to engage with a messaging campaign.
  
  The following characters are not recommended in attribute names: # : ? \ /. The Amazon Pinpoint console does not
  display attributes that include these characters in the name. This limitation does not apply to attribute values.
  
  @return Custom attributes that describe the endpoint by associating a name with an array of values. For example,
  an attribute named "interests" might have the values ["science", "politics", "travel"]. You can use these
  attributes as selection criteria when you create a segment of users to engage with a messaging campaign.
  
  The following characters are not recommended in attribute names: # : ? \ /. The Amazon Pinpoint console
  does not display attributes that include these characters in the name. This limitation does not apply to
  attribute values.