from metaflow import FlowSpec, step, card, conda, current

def with_requirements(f):
    def read_reqs():
        with open('requirements.txt') as f:
            for line in f:
                yield line.split('==')
    return conda(libraries=dict(read_reqs()))(f)

class ReqsFlow(FlowSpec):
   
    @with_requirements
    @card
    @step
    def start(self):
        import numpy
        self.matrix = numpy.arange(1, 10)
        self.next(self.end)

    @step
    def end(self):
        pass

if __name__ == '__main__':
    ReqsFlow()