Can be inferred from the exons, this is not implemented yet

def junctions(self):
    """Can be inferred from the exons, this is not implemented yet"""
    if len(self.exons) < 2: return []
    junctions = []
    for i in range(1,len(self.exons)):
      junctions.append(Junction(self.exons[i-1],self.exons[i]))
    return junctions