def getScore(self, chrom, point):
e = self.getElement(chrom, point)<EOL>if e is None:<EOL><INDENT>return None<EOL><DEDENT>return e.score<EOL>
@summary: get the value (float) that is intersected by the given point
          returns None if there is no such element
@return:  a float
@raise WigFileError: if more than one element intersects the point