input: Write a python function to remove rows with missing values in a DataFrame.
  assert remove_missing_values(pd.DataFrame({'name': ['John', 'Steve', 'Harry'], 'age': [22, None, 25], 'nationality': ['Nigerian', 'American', 'British']})).equals(pd.DataFrame({'name': ['John', 'Harry'], 'age': [22, 25], 'nationality': ['Nigerian', 'British']}))
  assert remove_missing_values(pd.DataFrame({'name': ['Alice', 'Bob'], 'age': [30, None], 'nationality': ['Canadian', 'Dutch']})).equals(pd.DataFrame({'name': ['Alice'], 'age': [30], 'nationality': ['Canadian']}))
output: import pandas as pd
  
  def remove_missing_values(df):
      return df.dropna()