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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def get_region (self, rs,cs, re,ce):
        '''This returns a list of lines representing the region.
        '''

        rs = constrain (rs, 1, self.rows)
        re = constrain (re, 1, self.rows)
        cs = constrain (cs, 1, self.cols)
        ce = constrain (ce, 1, self.cols)
        if rs > re:
            rs, re = re, rs
        if cs > ce:
            cs, ce = ce, cs
        sc = []
        for r in range (rs, re+1):
            line = u''
            for c in range (cs, ce + 1):
                ch = self.get_abs (r,c)
                line = line + ch
            sc.append (line)
        return sc