load shapefile fiona multiline intersection
from shapely.geometry import shape
import fiona
Multilines = MultiLineString([shape(line['geometry']) for line in fiona.open("lines.shp")])
Poly = shape(fiona.open("one_poly.shp").next()['geometry'])
Multilines.intersection(Poly)
<shapely.geometry.multilinestring.MultiLineString object at 0x1093285d0>