<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def from_where(cls, where):
 """ Factory method for creating the top-level expression """

        if where.conjunction:
            return Conjunction.from_clause(where)
        else:
            return cls.from_clause(where[0])