class Solution(object):

```
def generate(self, numRows):
"""
:type numRows: int
:rtype: List[List[int]]
"""
if numRows==0:
return [[]]
elif numRows==1:
return [[1]]
elif numRows==2:
return [[1],[1,1]]
else:
return (self.generate(numRows-1)).append(self.nextline(self.generate(numRows-1)))
def nextline(self,listOflist):
result=[1]
for i in range(len(listOflist[-1])-1):
result.append(listOflist[-1][i]+listOflist[-1][i+1])
result.append(1)
return result
```