* "Mean" is not a correct word in Spanish. It is an English word meaning "malo" (bad) or "cruel" in Spanish.
* "Toma una clase de" means "takes a class of". This phrase implies a subject, for example, "toma una clase de arte" (takes an art class).
To correct the sentence, we need to figure out what Martín is taking a class of. Here are some possibilities:
1. If Martín is taking a class about meanness or negativity:
* Martín es artista y toma una clase sobre la maldad. (Martín is an artist and takes a class about evil.)
* Martín es artista y toma una clase de psicología oscura. (Martín is an artist and takes a class of dark psychology.)
2. If Martín is taking a class in a specific art form:
* Martín es artista y toma una clase de pintura. (Martín is an artist and takes a painting class.)
* Martín es artista y toma una clase de escultura. (Martín is an artist and takes a sculpture class.)
3. If Martín is taking a class in a specific skill related to his art:
* Martín es artista y toma una clase de marketing. (Martín is an artist and takes a marketing class.)
* Martín es artista y toma una clase de fotografía. (Martín is an artist and takes a photography class.)
Please provide more context about what type of class Martín is taking, and I can help you create a grammatically correct sentence!