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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 inject(self, solutions):
 """inject a genotypic solution. The solution is used as direction relative to the distribution mean to compute a new candidate solution returned in method `ask_geno` which in turn is used in method `ask`. """

        if not hasattr(self, 'pop_injection_directions'):
            self.pop_injection_directions = []
        for solution in solutions:
            if len(solution) != self.N:
                raise ValueError('method `inject` needs a list or array'
                    + (' each el with dimension (`len`) %d' % self.N))
            self.pop_injection_directions.append(
                array(solution, copy=False, dtype=float) - self.mean)