Is an expert witness permitted to testify regarding the culture, habits and psychology of a criminal gang?

Generally, for the purposes of proving the gang enhancement, an expert witness is permitted to testify regarding the culture, habits, and psychology of criminal gangs. The expert, in response to a hypothetical question modeled after the alleged crime, may opine as to the motivation for the defendant's actions if the opinion falls within the witness's expertise regarding the culture of criminal gangs. (People v. Ward (2005) 36 Cal.4th 186, 210, 30 Cal.Rptr.3d 464, 114 P.3d 717.) However, a "crime may not be found gang related ... based solely upon the defendant's criminal history and gang affiliations. The crime itself must have some connection with the activities of a gang." (People v. Martinez (2004) 116 Cal.App.4th 753, 761, 10 Cal.Rptr.3d 751, italics omitted.)