I wanna python expert solutions and please if you cant do it fully dont post anything. Answers will be related to python oop

PLEASE EXPLAIN THIS CODE STEP BY STEP (EVERYTHING)

class DataReader: def -init-(self): self. students = [] 3e1f.col titles = [] def read (self, filepath): fp open (filepath) lines tp.readlines() tp.close () tor i in range (o, len(1ines)): line lines[i].split("I") if (i--0): for col in 1ine: self.col_titles.append (col.strip)) else: student- tor j in range (0, len(self.col_titles)): studenttself.col titles 1ine.strip) self.students.append (student) def grade histogram (): grade_names ["AA, "BA","BB","CB","CC, "DC","DD""FD,"FF" counts-[0, 0, 0, 0, 0, 0, 0, 0, 0 or student in self.students: grade student"grade" ] index grade_names.index (grade) counts[index]1 for i in range (, len(counts)): print ("to [fdj: "$(grade-names[1], counts[1], "*"fcounts[1])) det average (type="total", exceptions=[], in-0, nax=100): avg 0.0 n 0.0 for student in self.students: if studentl"lastname"] in exceptions: continue score-float(student[ type]) if (score> in and scorec=max): avg += score n+= 1 return avg